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Biomolecules are substances that are found naturally inside living cells. Biomolecules comprise macromolecules such as carbohydrates, proteins, lipids, as well as nucleic acid. Also, it includes smaller molecules such asprimary and secondary natural compounds and metabolites. Biomolecules consist mainly of hydrogen and carbon, along with oxygen, nitrogen sulfur and the phosphorus. Biomolecules are huge molecules made up of many atoms that are covalently linked. Different classes of Biomolecules There are four major categories of biomolecules They are: i. Carbohydrates II. Lipids II. Proteins iv. Nucleic acids. Best NEET Coaching in Guwahati.
Carbohydrates are an excellent energy source. Carbohydrates (polysaccharides) are long chains of sugars. Monosaccharides are sugars that consist of three to seven carbon atoms. They are free of aldehyde group or ketone group which functions as reducing agents. They are also known as sugars with a reduced structure. Disaccharides are composed by two monosaccharides. The bonds between two monosaccharides is called glycosidic bonds. Monosaccharides and Disaccharides are sweet, crystalline , and water-soluble compounds. Polysaccharides are monosaccharides that are polymers. They are non-sweet or complex carbohydrates. They are not soluble with water and do not appear in crystal form. – Example: glucose, fructose, sucrose, maltose, starch, cellulose etc.
Lipids consist of long chains of hydrocarbons. Lipid molecules contain a huge quantity of energy, and are stored energy molecules. Lipids are usually esters of fatty acids , and are the building the blocks in biological membranes. The majority of lipids are polar in head and non-polar tail. Fats acids can be saturated or unsaturated. Best NEET Coaching in Guwahati. Lipids that are present in biological membranes fall into three types according to the kind of hydrophilic head that is found: Glycolipids are the liquids that have the oligosaccharides that have 1-15 saccharide residues. They have an positively charged head that are connected to negatively charged groups of phosphate. Sterols have a head that contains an rings of steroid. An example of a of a steroid. A sample of lipids, such as oils, glycolipids, fats, phospholipids and more.
Acids are organic compounds that contain heterocyclic rings. Nucleic acid is a the nucleotide polymer. Nucleotides comprise nitrogenous base, pentose sugar, and a phosphate group. A nucleoside is composed of nitrogenous base that is attached to pentose sugar. The bases that are nitrogenous include adenine, guanine and Thyamine, Cysine, and Uracil. Polymerized nucleotides make DNA and RNA that are the genetic material. Best NEET Coaching in Guwahati.
Proteinns are heteropolymers composed comprised of stings of amino acid. Amino acids are linked through the peptide bond that forms between the carboxyl and amino group of the successive amino acids. Proteins are made up of 20 different amino acids according to the number of amino acids and arrangement of the amino acids. Best NEET Coaching in Guwahati. There are four types of proteins: (i) The primary structure Proteins – Proteins are a long chains of amino acids, arranged in a specific order. They are functional proteins. (ii) secondary structure of proteins The long chains of proteins is folded and put in a helix form that is where amino acids are interconnected through the creation from hydrogen bonds. This is known as”the pleated sheet. Silk fibres are an example. (iii) Tertiary structural structure of proteins Long polypeptide chains are more stable by coiling and folding, and by the creation of hydrophobic or ionic bonds or disulphide bridges. this results in the tertiary shape of protein. (iv) The quaternary structures of protein – when the protein is made up of multiple polypeptides or subunits it is said to constitute the quaternary structure protein. Example: Haemoglobin, insulin.
The functions of Biomolecules Carbohydrates supply the body with energy and fuel, it assists in the good functioning of the brain, heart , nervous and immune system, as well as digestion. A lack of carbohydrates in the diet can cause fatigue and diminished mental functioning. Each protein in your body serves a purpose and some proteins offer structural support, assist in the body’s movement as well as protection against infection and germs. Proteins may include hormones, antibodies enzymes, and contractile proteins. Lipids, the main reason for lipids to be found in our bodies are storage of energy. Best NEET Coaching in Guwahati. The structural membranes comprise the lipids that form an insulator and regulate the movement of materials into and out of cells. Lipid hormones, like sterols, help in mediating communication between cells. Nucleic Acids are DNA and RNA. They contain genetic information within cells. They also assist in the production of proteins, via the process of transcription and translation.
Carbohydrate is an organic compound, it comprises of only oxygen, carbon and hydrogen. The oxygen to hydrogen ratio usually is 2:1. The most common formula is Cn(H2O)n . Carbohydrates are hydrates made of carbon. Technically, they are ketones and polyhydroxy aldehydes. Carbohydrates can also be referred to as saccharides The term saccharide originates from the Greek words sakkron which refers to sugar. Nomenclature and classification of carbohydrates – The carbohydrates can be classified into three main classes based on the extent to which they undergo hydrolysis or, when they do, on the amount of products produced. 1. Monosaccharides: Monosaccharides are polyhydroxy aldehydes, or ketones that are not decomposed through hydrolysis to produce simpler carbohydrate. e.g. Glucose, fructose, Galactose etc. Best NEET Coaching in Guwahati.
2. Oligosaccharides The Oligosaccharides (Oligo small) are carbohydrates that produce an exact quantity (2-9) of monosaccharide molecules upon hydrolysis. 2.) Disaccharides – which yield two monosaccharides molecules upon hydrolysis. They have molecular formulas of C12H22O11.e.g. Sucrose, maltose, etc.) Trisaccharides: These produce three monosaccharides upon hydrolysis. Their molecular formula of C18H32O16. C) Tetrasaccharides – Which yield four monosaccharides molecules upon hydrolysis. Their molecular formula of C22H42O21. eg: Stachyose [gal(a1-6)gal(a1-6)glu(a1-2b)fru]3. Polysaccharides: The carbohydrate that have a greater molecular weight that yield numerous monosaccharide molecules during hydrolysis. E.g. Starch, glycogen, Dextrin, Cellulose etc. In general, monosaccharides and Oligosaccharides are solids that are crystallized, that dissolve in water and are sweet in taste and are collectively referred to as sugars. The polysaccharides on the other hand , are non-soluble, amorphous and tasteless, and are referred to as non-sugars.
1.1 Different between monosaccharaides, oligosaccharides and Polysaccharides Test for carbohydrate: Character Monosaccharaides Oligosaccharides Polysaccharides No. in sugar molecules 1- 9 more than 9 Glycoside bonds are not Presently Molecular Weight Low Moderate High Taste Sweet Very sweet taste , no taste Solubility Soluble insoluble Nature always reducing sugar. May or might not be always not reducing sugar. Examples include Glucose fructose, Galactose Sucrose, Maltose Starch Glycogen Cellulose.1.2 Best NEET Coaching in Guwahati.Carbohydrates’ propertiesGeneral characteristics of carbohydrates Carbohydrates are energy reserves, they also store the metabolic intermediates and fuels. Best NEET Coaching in Guwahati. The sugars deoxyribose and Ribose form the structural frame of genetic material, DNA and RNA. Polysaccharides, like cellulose, are the essential structural components of cells of bacteria as well as plants. Carbohydrates are connected with proteins as well as lipids which are essential to cell interactions. Carbohydrates are organic molecules; they are ketones or aldehydes with numerous hydroxyl groups. 1.2.1
Optical Activity – It’s the motion of plane polarized light creating (+) glucose and (+) glucose. Diastereo isomeers is alters the configuration with respect to C2 or C3 in glucose. Example: Mannose, galactose. Annomerism is the spatial configuration in relation to the carbon atom of the first in aldoses and the second carbon atoms in ketoses. 1.2.2 Physical characteristics of Carbohydrates: Steroisomerism Compound shaving has the identical structural formula, however they differ in their spatial configuration. For example, glucose is composed of two isomers in relation to the the penultimate carbon atom. They are D-glucose and L-glucose. Chemical Properties of Carbohydrates- Ozazone Formation by the phenylhydrazine. Benedicts test. Best NEET Coaching in Guwahati. Oxidation Reduction to Alcohols structure of carbohydrates – There are three kinds of representations for the structural structure for carbohydrates. (i) open chain structures. (ii) Hemi-acetal structure. (iii) Haworth structure. Integrated JEE/NEET best Coaching. Physical characteristics of Carbohydrates: Steroisomerism Compound shaving has the identical structural formula, however they differ in their spatial configuration. For example, glucose is composed of two isomers in relation to the the penultimate carbon atom. They are D-glucose and L-glucose.
The functions that are performed by Carbohydrates Carbohydrates are the main energy source for many animals.They provide a rapid sources of power. Glucose is broken down through glycolysis/kreb’s cycle in order to create ATP. It is the main source of the energy storage. It is stored in glycogen in animals, and as starch in plants. The stored carbohydrates serve as an sources of energy in place of protein. Carbohydrates play a role in the biosynthesis of proteins and fats. Carbohydrates help regulate nerve tissue, and are the brain’s energy source. Carbohydrates are paired with proteins and lipids, forming receptor molecules, surface antigens Vitamins and antibiotics. They create structures and protectants such as in the cells of plants and microorganisms. In animals , they are an important component of connective tissue. They are involved in the process of biological transport as well as cell-cell communication, and the stimulation of growth factor. Carbohydrates with high fiber content aid in preventing constipation.
They also aid in the improving the function of the immune system. Examples of Carbohydrates Monosaccharides : Galactose, glycerose, glucose and erythrose, ribose fructose, ribulose. – Oligosaccharides Maltose, lactose sucrose, raffinose stachyose. Polysaccharides – Starch glycogen and cellulose. Pectin, inulin, hyaluonic acids. Diets high in carbohydrates are known as strachy food. They can be found in legumes as well as starchy vegetables, whole-grain cereals, and breads. Physical characteristics of Carbohydrates: Steroisomerism Compound shaving has the identical structural formula, however they differ in their spatial configuration. For example, glucose is composed of two isomers in relation to the the penultimate carbon atom. Best NEET Coaching in Guwahati. They are D-glucose and L-glucose. They are also naturally present with minerals and vitamins found in milk fruit, milk, and other products. They can also be present in refined and processed items like sweets carbonated beverages, candy, along with table sugar. A few examples are table sugar, carbonated beverages and candy. Polysaccharides The name of Polysaccharide Composition Obscurrence Functions Starch polymer of glucose that has straight sugar molecules (amylose) and a branched sugar molecules (amylopectin) In a variety of plant species , they are the main source of reserves of carbohydrate Glycogen polymer from glucose animals (equivalent to Starch) Storage of food reserves Inulin Polymer of fructose found in the roots as well as in tubers (like Dahlia) Storage of reserves food Cellulose Polymer made of glucose.
It is found in the cell wall of plants. cell wall pectin polymer of galactose and its derivatives . Plant cell wall cell wall matrix Hemicellulose Polymer of sugar acids and pentoses cell wall cell wall matrix Lignin polymer of glucose Cell wall (dead cells similar to Sclerenchyma) The cell wall matrix is Chitin polymer made of glucose Bodywalls of arthropods. In some fungi, exoskeleton impermeable to water. Murein Polysaccharide is cross-linked with amino acids. Cell walls of protokaryotic cells. Structural protection Hyaluronic acid polymer made of sugar acids. It is a connective tissue matrix, outer coating of mammalian eggs. Ground substance Protection Heparin close to chrondroitin connective tissues Anticoagulant gums and Mucilages are polymers composed of sugars as well as sugar acids . Gums that are either trees or bark. Mucilages – flowers retain water during dry seasons. Best NEET Coaching in Guwahati. Physical characteristics of Carbohydrates: Steroisomerism Compound shaving has the identical structural formula, however they differ in their spatial configuration. For example, glucose is composed of two isomers in relation to the the penultimate carbon atom. They are D-glucose and L-glucose.
Lipids comprise a heterogeneous class that comprises water insoluble (hydrophobic) organic substances that are extracted from tissues with nonpolar solvents. Because of their insolubleness within aqueous solutions. Body lipids are typically found in compartments such as that of membrane-associated lipids and droplets of triacylglycerol within Adipocytes, or in plasma, in conjunction with protein such as lipoprotein particles or in albumin. Lipids are a significant fuel source for our bodies and also create the hydrophobic barrier. Lipids perform additional roles in the body. For example certain fat-soluble vitamins perform the ability to regulate or coenzyme as well as the prostaglandins and steroids play an important role in the management of the body’s balance. 2.1 The general characteristics of lipids :Lipids are largely insoluble within water. They are also dissolvable in non-polar solvents such as chloroform, ether and Methanol. Lipids are high in energy content and are processed into releasing calories. Lipids are also electrical insulators. They protect nerve axons. They are saturated with fat acids, and are solid at room temperature. Examples include animal fats. The plant fats contain no saturated and they are liquid at room temperature.
Pure fats are colourless and possess a very bland flavor. The fats are only water-soluble and are classified as hydrophobic compounds. They are and easily soluble in organic solvents, such as acetone, benzene and ether. Melting point for fats varies in the long-term chain that is made up of the constituent fatty acid and on the level of unsaturation. Best NEET Coaching in Guwahati. Geometric isomerism: the presence of double bonds inside the unsaturated fat acid in the lipid molecule causes geometric or isomerism that is cis-trans. Fats can be insulators but they are poor conductors of heat. Emulsification is the procedure by which the mass of lipids is converted into small droplets of lipid. Emulsification occurs before fats are absorb by the intestinal wall. The fats are then broken down by lipases, an enzyme, to create fatty acids as well as Glycerol. The process of hydrolysis of fats through the alkali process is known as saponification. This reaction causes an increase in glycerol as well as the salts that are formed from fatty acids, referred to as soaps. Hydrolytic rancidity occurs through the development of microorganisms that release lipases-like enzymes. These break down fats into glycerol as well as free fat acids.
1. Simple lipids: Esters from fat acids that contain various alcohols. A. Fats esters from fatty acids that contain the glycerol. They are fats in their liquid form. They are also known as. Waxes are esters of fatty acids having higher molecular weight monohydric alcoholics. 2. Complex lipids: Esters made from the fatty acids with groups in addition to alcohol and an saturated fatty acid. A. Pholipids are Lipids that contain additional the fatty acids as well as an alcohol and a phosphoric acid residue. They often contain nitrogen-containing bases, as well as substituents for them such as in glycerophospholipids there is an alcohol called glycerol while in sphingophospholipids, the alcohol is sphingosine. b. Glycolipids (glycosphingolipids): Lipids containing a fatty acid, sphingosine, and carbohydrate. C. Others complex lipids Lipids, such as sulfolipids or aminolipids. Lipoproteins could also be put in this class. Best NEET Coaching in Guwahati.
3. Precursor and derived oils This includes fat acids, glycerol steroids, alcohols of other types fat aldehydes, hydrocarbons, ketone bodies, lipid-soluble vitamins , and hormones.2.3 Essential acid fatty acids :Two of these acids are essential for diets of humans. (i) Linoleic acid, which is the precursor to arachidonic acid, which is the base for prostaglandin synthesis. (ii) the a-linolenic acids is the main ingredient in expansion and growth. A deficiency in essential fatty acids could cause skin dermatitis that is scaly, along with neurological and visual impairments. Linolenic acid Linoleic acid Regulating Blood Cholesterol Levels – Fats and cholesterol cannot dissolve in blood and are consequently packaged with proteins (to form lipoproteins) for transport o Low density lipoproteins (LDL) carry cholesterol from the liver to the rest of the body o High density lipoproteins (HDL) scavenge excess cholesterol and carry it back to the liver for disposal – Hence LDLs raise blood cholesterol levels (‘bad’) while HDLs lower blood cholesterol levels (‘good’) – High intakes of certain types of fats will differentially affect cholesterol levels in the blood o Saturated fats increase LDL levels within the body, raising blood cholesterol levels o Trans fats increase LDL levels and decrease HDL levels within the body, significantly raising blood cholesterol levels o Unsaturated (cis) fats increase HDL levels within the body, lowering blood cholesterol levels.
Lipid Health Claims – There are two main health claims made about lipids in the diet: o Diets rich in saturated fats and trans fats increase the risk of CHD o Diets rich in monounsaturated and polyunsaturated (cis) fats decrease the risk of CHD Health Risks of High Cholesterol – High cholesterol levels in the bloodstream Best NEET Coaching in Guwahati. lead to the hardening and narrowing of arteries (atherosclerosis) – When there are high levels of LDL in the bloodstream, the LDL particles will form deposits in the walls of the arteries – The accumulation of fat within the arterial walls leads to the development of plaques which restrict blood flow – If coronary arteries become blocked, Coronary Heart Disease (CHD) will result – this includes heart attacks and strokes Examples of Lipids – Fatty acids – Oleic acid, Linoleic acid, Palmitoleic acid, Arachidonic acid.
1. Lipids are food material. They provide foodthat is extremely rich with calorific values. One gram of lipid is responsible for 9.3 Kilocalories of heat. 2. Food reserve: Lipids are not soluble in water and thus can be stored inside the body to form a food reserve. 3. Lipids are structural components that are an essential component within the cell’s membrane. 4. Fats that are used for heat insulation are recognized for their excellent capacity to withstand heat. A large amount of fat is found in the subcutaneous layer in marine mammals, such as whales, as well as in animals that live within colder climates. 5. Absorption of fatty acids: Phospholipids are essential to the absorption and transfer of fatty acids. 6. Hormone synthesis: The sexual hormones, adrenocorticoids and cholic acids, as well as vitamin D all are created from cholesterol the non-steroidal fat.Best NEET Coaching in Guwahati.
7. Lipids are vitamin carriers. They are the natural carriers of fat-soluble vitamins like Vitamin A, D as well as E.8. Lowering blood cholesterol Chocolates and beef, particularly the latter, were believed to be responsible for a variety of heart-related diseases because they contain saturated fatty acids that raise blood cholesterol levels and block the arterial passage. However, studies carried out by the University of Texas by Scott Grundy and Andrea Bonanome (1988) suggest that at the very least the one saturated fat acid, stearic acid, which is a key component of beef fat and cocoa butter and beef fat, doesn’t raise the level of cholesterol in blood at all. The study placed 11 people on three cholesterol-free liquid diets over three weeks with random ordering. One of the diets was high in palmitic acid which is a popular cholesterol booster. The second was rich with oleic acid and the final one was the stearic acid. If compared to a diet high in palmitic acid high blood cholesterol was reduced by 14% when subjects were put on the stearic-acid diet as well as 10% less for those on the oleic acids diet.
9. Antibiotic agent. Squalamine, a synthetic steroid extracted from shark blood is proven to act as an antibiotic as well as an antifungal agent that has a high level of action. This could be the reason why sharks aren’t prone to contracting infections and rarely develop cancer.Proteins are big macromolecules, also known as biomolecules, comprised of one or two large chains of amino acids. Proteins are considered to be the living organisms’ building blocks.
Proteins are among the most abundant macro-molecules in intracellular cells. They give structure, protection for the multicellular body as hair, skin cartilage, callus, muscles, ligaments, tendon. Proteins regulate and regulate the body’s chemistry, in the form of enzymes, hormones, immunoglobulins and other. Best NEET Coaching in Guwahati.
The organic molecules of proteins are they are composed of nitrogen as well as carbon, oxygen and hydrogen. Proteins are among the most significant biomolecules, they are the main component of the cytoplasm within the cell. Proteins are the main structural components of the body’s tissues. Proteins are composed from amino acids. Proteins supply energy and warmth to the body. They also assist in the process of building and repairing. There are only tiny amounts of protein are stored within the body, as they are able to be utilized rapidly upon demand. Proteins are regarded as the building blocks that compose muscles, bones hair, as well as other elements in the body. Proteins, like enzymes, are functional components that play a role in the metabolic process. Blood haemoglobin, antibodies are also composed of proteins. Proteins possess a molecular weight between 5 and 300 Kilo-Daltons. Best NEET Coaching in Guwahati.
3.1.1The physical properties of proteins: Proteins are tasteless and colorless. They are homogeneous, and crystallized. Proteins can vary in their shape and can be simple crystalloids or longer fibrilar forms. Protein structures can be classified into two distinct types: fibrilar proteins and the Globular protein. Globular proteins have a spherical shape and can be found in plants. They are thread-like proteins, and they are common in animals. They generally contain large molecular masses that range between 5 X 103 to 1 x 1106 . Due to their massive sizeof proteins, they exhibit a variety of colloidal properties. The rates of diffusion for proteins are very slow. Proteins exhibit the Tyndall effect. Proteins are known to alter their properties, similar to denaturation. In many cases, it is followed up by the process of coagulation. Denaturation can be a result of chemical or physical agents.
Physical agents include the shaking of ice, etc. Chemical agents are similar to Ultrasonic, radioactive, and X-ray radiations. Proteins, like amino acids have an amphoteric characteristic i.e. they could be used like Acids or Alkalies. Since proteins are amphoteric by nature they can create salts that contain both anions and cations, dependent in the amount of charge they carry. Best NEET Coaching in Guwahati. The solubility of proteins is dependent on pH. Solubility at its lowest is at the isoelectric level, and the solubility rises with increasing pH or acidity. All proteins exhibit the polarized light plane toward the left i.e. Laevorotatory. The oils and fats are Animal fats: Butter Lard, lard, human fat Herring oil, and other fats. Plant oils: Coconut oil Corn and Palm oils, Sunflower oil, Peanut. Waxes – Spermacti Beeswax, Carnauba wax. – Phospholipids Lecithins Cephalins, Plasmoalogens, Phosphatidyl inositols, Sphingomyelins. – Glycolipids – Kerasin, Phrenosin, Nervon, Oxynervon. – Steroids – Cholesterol. – Terpenes – Monoterpenes, Sesquiterpenes, Diterpenes, Triterpenes. – Carotenoids – Lycopene, Carotenes, Xanthophylls.
3.1.2 The chemical properties of proteins: Proteins that are hydrolyzed with acidic substances, such as conc.HCl produce amino acids as a result their hydrochlorides. The hydrolysis of proteins with alkaline substances result in the hydrolysis of some amino acids such as arginine serine, cysteine and so on. Additionally, the optical properties of amino acids disappears. When proteins react with alcohols produce the ester-like counterparts. This process is called esterification. Amino acids react with amines to create an amide. If free amino acids or proteins are believed to interact with minerals, such as HCl the acid salts are created. In the event that amino acid within alkaline media reacts several acid chlorides, an the acylation reaction occurs. Best NEET Coaching in Guwahati. This is known as Xanthoproteic test – When boiling proteins, conc. HNO3, yellow-colored color is formed due to the presence of a benzene rings. – Folin’s test – This is a specific test for tyrosine amino acid, where blue color develops with phosphomolybdotungstic acid in alkaline solution due to presence of phenol group. Integrated JEE/NEET Best tutors in Barowari.
3.2 structure of proteins: The structure of proteins are made by the polymerization process of just 20 amino acids in linear chains. Proteins are the amino acids that are polymers. Proteins’ structure is extremely complex, and could be classified into four stages of structure. 1. Primary structure: The linear sequence of amino acids, which forms proteins’ backbone (polypeptides). Examples of proteins with primary structures are Hexosaminidase and Dystrophin. 2. Secondary structure: The spatial arrangement of protein by twisting its polypeptide chain. A good example of protein having an additional form is the Myoglobin. 3. Tertiary structure: The three-dimensional structure of an actual protein. The force that acts to keep the polypeptide chain together in this final arrangement: Polar/Nonpolar Interactions Hydrogen Bonds van der Waals Forces Ionic Interactions Disulfide Bonds Examples of proteins that have a Tertiary structure include Globular Proteins (Enzymes) as well as Fibrous Proteins.
4. Quaternary structure: Some of the proteins consist of multiple polypeptide chains that are referred by the term subunits. The arrangement of the spacial subunits is referred to as Quaternary Structure. One example of proteins that have the Quaternary structure include DNA polymerase and Ion channels. 3.2.1 Best NEET Coaching in Guwahati. Secondary Structure of Proteins. Shape of Alpha Helix: Alpha Helix is a right-handed coiled rod-like structure. Beta Pleated Sheet Beta sheet is an envelopFormation of Alpha Helix: Hydrogen bonds develop inside the polypeptide chain to form a helical structure. Beta Pleated Sheet Beta sheets form by joining several beta strands using H bonds. Bonds o Alpha Helix: Alpha Helix is a an H-bonding scheme of n + 4. i.e. Hydrogen bonds form between the N-H the amino group in one acid with the C=O group of a different amino acid that is put in four residues earlier.Beta Pleated Sheet: Hydrogen bonds are formed between the C=O and N-H groups in an the peptide chain that is adjacent to it the -R group.
Alpha Helix: The amino acids are located to the outside of the helix. Beta Pleated Sheet The -R groups are located the inside and outside of the sheet.Number of Alpha Helix: This could be an individual chain. Beta Pleated Sheet It cannot be one beta strand, there have to be at least two. The type Alpha Helix: This has only one type. Beta Pleated Sheet: It can be parallel, anti-parallel , or mixed. The Alpha Helix has the following qualities 100o rotation, 3.6 residues per rotation and 1.5 Ao rise from one alpha carbon to the next the Beta Pleated Sheet 3.5 Ao rise between residues Amino Acid Alpha Helix: The Alpha helix prefers amino acid chain side chains that can protect and cover the backbone Hbonds inside the center part of the. Beta Pleated Sheet The extended structure leaves ample space available for amino acid chain side chains. Thus, amino acids with big bulky side chains are preferring the beta structure. Best NEET Coaching in Guwahati.
Preference o Alpha Helix: Alpha helix prefers Ala, Leu, Met, Phe, Glu, Gln, His, Lys, Arg amino acids. o Beta Pleated Sheet: Beta sheet prefers Tyr, Trp, (Phe, Met), Ile, Val, Thr, Cys. The Alpha Helix Secondary Structures of Proteins: Beta Pleate Antiparallel: where the adjacent chains of polypeptides run in the opposite directions. Beta Pleate Parallel: Adjacent polypeptide chains running in same direction.3.3 Protein Classification. 1. Classification of Proteins based on Shape. Globular or Corpuscular Proteins Globular proteins Globular proteins have an axial ratios that are less than 10, but not lower than three or four. They are tightly folded and coiled, and have the characteristic of being ovoid or spherical in shape. They are generally liquid in water and the aqueous medium. – Example: Insulin, plasma albumin, globulin enzymes. Axial ratio, for any type of structure or form that has two or more axes is the proportion to the distance (or size) of the axes in relation to one another – that is, the longer one divided by shorter.
In the field of chemistry or materials science the Axial ratio (symbol”P”) uses the symbol P to define the rigidity of rods and molecules. It is described in terms of length divided by rod’s diameter. ii. Fibrous or Fibrillar proteins – They have an axial ratios that exceed 10; therefore, they look like long ribbons or fibres in form. Best NEET Coaching in Guwahati. They are typically found in mammals, and aren’t dissolvable in water or in the solution of dilute acid. Fibrous proteins help in structural protection and protection. – Example: Collagen, Keratin, Elastins, Fibroin.2. Classification of Proteins Based On Solubility and Composition. (i) Simple Proteins, or Holoproteins- They are composed from a single type of amino acid. It is used as a structural component. Upon decomposition by acids they release amino acids. They are mostly globular types of proteins, except for the scleroproteins which are naturally fibrous. Simple proteins are separated based on their solubility.
A) Histones and Protamines These proteins are found only in animals and are essential proteins. They have a simple structure and are low molecular. are water-soluble and do not get coagulated through heat. They are essentially basic because of their high proportion of arginine, lysine. o Example: Protamines – salmine, clupine, cyprinine; Histones – nucleoshistones, globin. B) Albumins- They’re abundant in nature and are typically in seeds. They dissolve in water as well as dilute solutions of bases, acids and salts. o Example: Leucosine, legumeline, serum albumin. C) Globulins are made up of two kinds, pseudoglobulins, which dissolve in water. The other is euglobulins, which are not soluble within water. Best NEET Coaching in Guwahati. They are coagulated using heating. o Example: Pseudoglobulin, serum globulin, glycinine. etc. etc.) and Albuminoids. They are found in animals and are identified as the animal Skeleton proteins. They are insoluble in water, as well as in dilute solutions of acids, bases and salts. Best NEET Coaching in Guwahati.
(ii). Complex Proteins, Conjugated or Heteroproteins: These are proteins made of amino acids as well as various organic substances. The group that is not amino acids is referred to as the prosthetic group. Complex proteins are classified according to the kind of prosthetic group they belong to. A) The Metalloproteins are proteins that are linked to a variety of metals. o Example: casein, collagen, ceruloplasmin, etc. b) Chromoproteins are proteins that interact with a color. o Example: Myoglubin, hemocyanin, cytochromes, flavoproteins, etc. C) Glycoproteins as well as Mucoproteins These proteins are composed of carbohydrates, which form their prosthetic groups. o Example: Glycoproteins – egg albumin, serum globulins, serum albumins; Mucoproteins – Ovomucoid, mucin etc. D) Phosphoproteins are linked to phosphoric acids. o Example: casein. e) Lipoproteins: Proteins that form complexes that contain lipids are known as lipoproteins. For example, lipovitellin is one of the blood lipoproteins. f) Nucleoproteins are compounds that contain nucleic acid and proteins.
Example: Nucleoproteins, nucleohistones, nuclein. G) Derived Proteins are proteins that originate by the reaction of enzymes, heat or chemical reactions. Derived proteins come in two kinds, mostly the derived proteins as well as secondary derivative proteins. Primary derived proteins, also known as derivatives of proteins, where their size does not get modified in any way.,. Primarily derived proteins are divided into three categories namely Proteans, Infraproteins and Coagulated proteins. Best NEET Coaching in Guwahati. Examples: edestan, egg-white coagulated. Secondary protein derived from. In secondary derived proteins there is hydrolysis, consequently the molecules have a smaller size than proteins that they were originally. They further categorize them into three types: Polypeptides, Peptones, and Proteoses. EGG PROTEINS COMPOSITION of EGG White Protein Percentage Total protein 10- 11 10% (on basis of wet basis); 82.8% (on dry basis) Ovalbumin accounts for 70 percent of all proteins Conalbumin 99 Ovomucoid 1.3% Globulins Lysozyme (G1) 2.6 percent Lysozyme (G2) 77 76% Lysozyme (G3) 7.7 2 % of Mucin 0.06%
Proteins are seen in muscles, hair, skin and other tissues; they constitute the bulk of body’s non-skeletal structure. For instance, the protein keratin is found in nails as well as hair. Certain proteins act as hormones and regulate many bodily functions. For instance, insulin hormone is a protein , and it regulates blood sugar levels. Certain proteins function as enzymes that catalyze or aid with biochemical processes. Example: Pepsin and Tripsin. Certain proteins act as antibodies, they shield the body from the effects of invading species and substances. Proteins carry different substances within blood of various tissues. Examples: Haemoglobin is an oxygen transport protein. Contractile proteins assist in the contraction of muscle and cells in our body. Examples: Myosin is a contraction protein. – Fibrinogen a glycoprotein helps in healing of wounds. It stops blood loss and blocks the passage of bacteria. Proteins are big macromolecules or biomolecules composed of one or more lengthy chains of amino acid residues. Best NEET Coaching in Guwahati. Proteins are regarded as essential components of life. Proteins are among the most abundant macro-molecules in intracellular cells.
3.5 The general characteristics of proteins The organic molecules of proteins are they are composed of nitrogen as well as carbon, oxygen and hydrogen. Proteins are among the most vital biomolecules. they are the main part of the cytoplasm of the cell. Proteins are the main structural components of the body’s tissues. Proteins are comprised by amino acid. Proteins provide energy and heat to the body. They also assist in the process of building and repair. The body only stores very small amounts of proteins are stored within the body since they are used quickly upon request. Proteins are thought of as the foundations of the body which comprise muscles, bones, hair and various other components in the body. Proteins such as enzymes are functional components that play a into account metabolic processes. Antibodies, blood hemoglobin are also composed of proteins. Proteins are composed of molecular mass of 5 to 300 Kilo-Daltons.
3.5.1 The physical properties of proteins- Proteins are tasteless and colorless. They are homogeneous and crystallized. Proteins can vary in their shape and can be simple crystalloids or longer fibrilar forms. Protein structures can be classified into two distinct types namely, fibrilar and Globular proteins. Globular proteins have a spherical shape and can be found in plants. The fibrilar proteins are thread-like and they are common in animals. They generally contain large molecular masses that range between 5 x 103 to 1 x 10106 . Because of their huge sizeof proteins, they exhibit a variety of colloidal properties. Best NEET Coaching in Guwahati. Proteins’ diffusion rates are very slow. Proteins exhibit the Tyndall effect. Proteins are known to alter their properties, similar to denaturation. A lot of times, this process is followed by the process of coagulation. Denaturation can be a result of chemical or physical agents. Physical agents include the shaking of ice, and so on. Chemical agents are similar to the X-rays, radioactive, and ultrasonic radiations.
Proteins, like amino acids possess an amphoteric function i.e. they could serve like Acids as well as Alkalies. Since proteins are naturally amphoteric they can make salts using both cations and anions , based in the amount of charge they carry. Proteins’ solubility is contingent on the pH. The lowest solubility can be observed at the isoelectric point. The solubility grows with the increase in the acidity of alkalinity. All proteins exhibit the polarized plane towards the left i.e. the laevorotatory. Best tutors for Integrated JEE/NEET in Lakhtokia.3.5.2 The chemical properties of proteins- Proteins that are hydrolyzed with acidic substances, such as conc.HCl give amino acids as a result their hydrochlorides. When proteins are hydrolyzed with alkaline substances result in the hydrolysis of some amino acids, such as arginine serine, cysteine and so on. Also, the optical properties of amino acids disappears.Best NEET Coaching in Guwahati.
The reaction of proteins with alcohols produce the equivalent esters. This process is called esterification. The amino acid reacts with amines to create the amides. When amino acids that are free or proteins are believed to be able to take on mineral acid, such as HCl acid salts, the acid salts are created. In the event that amino acid in alkaline medium is reacted with several acid chlorides, an the acylation reaction occurs. Best NEET Coaching in Guwahati. This is known as Xanthoproteic test – When boiling proteins, conc. HNO3, yellow color appears due to the presence of the benzene ring. – Folin’s test – This is a specific test for tyrosine amino acid, where blue color develops with phosphomolybdotungstic acid in alkaline solution due to presence of phenol group
Enzymes : Nature and classification of the enzymes. Enzymes are biochemical catalysts (also called biocatalysts) which speed up biochemical reactions. In living living organisms. They are also taken from cells and used to catalyze a diverse spectrum of essential for commercial purposes. They play significant roles in the manufacturing of sweetening agents as well as alteration of antibiotics they are utilized in the manufacture of washing powders and other cleaning products. They are a major component in the development of analytical instruments and assays with clinical,Environmental and forensic applications. Best NEET Coaching in Guwahati. The term “enzyme” was first mentioned by German physiologist Wilhelm Kuhne , in 1878 when he was discussing the capacity of yeast to make alcohol fromsugars, and it’s an ancestor of sugars, and it is derived from the Greek word en (meaning “within”) and zure (meaning “yeast”).
In the latter part of the nineteenth century and into the early century, important advancements were made in.The extraction and characterization, and commercialization of many enzymes. it wasn’t untilIn the 1920s, enzymes crystallized, showing the catalytic function is linked with proteins.molecules. Over the next about 60 to 70 years, it was thought that all enzymes were proteins but by the 1980s, it was discovered that certain Ribonucleic Acid (RNA) molecules are capable of exerting catalytic effects. These RNAs, also called ribozymes are essential to the expression of genes. They play a significant role in gene expression. in the same decade, biochemists created the technology to create antibodies with catalytic properties. The so-called “abzymes” are extremely valuable as novel catalysts for industrial use and in the field of therapeutics. In spite of these notable exceptions the majority of traditional enzymology isand the rest of this essay is focused on proteins that have catalytic activities.In their capacity as catalysts, enzymes are needed only in small quantities and speed up the process.Best NEET Coaching in Guwahati.
reactions, without them being consumed in the course of the reaction. We typically describeenzymes are able of catalyzing the transformation from substrate molecules to product. Molecules as follows:Substrate Produce Enzymes can be powerful catalystsThe immense catalytic capacity of enzymes may best be expressed as an unchanging constant, kcat whichIt is also called the turnover rate, the turnover frequency or the turnover number. The constant represents the quantity of substrate molecules that could be transformed into product in one the enzyme molecules per unit of time (usually for a minute, or even per second). Examples of turnover rates. Values are provided in Table 1. For instance the single carbon anhydrase carbon molecule could be catalyst for theconversion of more than half a million of its substrates CO2 (CO2) and even water (H2O) (H2O) to create the bicarbonate (HCO3) every second — a incredible feat. Certain enzymes act as catalysts.
In addition to being extremely powerful catalysts, enzymes have remarkable specificityThey typically catalyze the conversion of one kind (or at the most, a variety of similar kinds) of substrate molecule into product molecules. Some enzymes demonstrate group specificity. For example, alkalinephosphatase. The enzyme is often found in laboratory sessions for students in the first year of their studies on the kinetics of enzymes). The removal of phosphate groups from many substrates. Best NEET Coaching in Guwahati. Other enzymes show much greater specificity, known as absolute specificity. For instance glucose oxidase exhibits nearly complete specificity to its substrate, bD-glucose.and almost no interaction in any other monosaccharides. As we will see in the future, this particularityis crucial in the analysis of many assays as well as devices (biosensors) that test the amount ofSpecific substance (e.g. glucose) in a complex mix (e.g. samples of urine or blood). The names of the enzymes and classification.
Enzymes usually have common names (often known as ‘trivial names’) which refer to the reactionthey catalyze, using their suffix of -ase (e.g. dehydrogenase and oxidase) however, specific proteolytic enzymes typically include the suffix in (e.g. trypsin, chymotrypsin, papain). Most often the name, which is a joke, also indicates the substrate upon the which the enzyme operates (e.g. glucose oxidase, alcohol dehydrogenase, pyruvate decarboxylase). However, some trivial names (e.g. invertase, diastase, catalase) offer little information on the substrate and the reaction in question. Due to the increasing difficulty and inconsistency with regards to the names of enzymes, International Union of Biochemistry set an Enzyme Commission to address this problem. The very first Enzyme Commission Report was published in 1961. It offered an approach that was systematic to the The naming of enzymes. In the sixth edition released in 1992, provided information on more than 3200 various. Supplements and enzymes released annually have now pushed this to 5 000. In this system each enzyme is identified by an acronym that is four parts Enzyme Commission (EC)number. Best NEET Coaching in Guwahati.
For instance the enzyme that has the simple name lactate dehydrogenase is the EC number 184.108.40.206 It is correctly referred to as l-lactate.+ Oxoreductase. The first portion in the EC number is a reference to the reaction the enzyme catalyzes (Table 2.). The remaining digits can have various significance based on what the chemical reaction being identified by the first by the first. For instance, within the category of oxidoreductase the second digit signifies the the hydrogen donation (Table 3) and the third digit indicates that the acceptor of hydrogen (Table 4.). This lactate dehydrogenase that has number EC number 220.127.116.11 is an oxygenoreductase (indicated by the first by the first) by the first digit) in the lactate molecule being an hydrogen source (second The digit) (digit 3) and NAD+, which is its hydrogen acceptor (third digit) which it is also the 26th enzyme classified within the class (fourth fourth). The structure of the enzyme as well as its binding to substratesThese enzymes, which are based upon amino acid are large proteins which range in dimensions ranging from less than 100 to over than 2 000 amino acid residues.
They can be placed in several polypeptide chains, which are bent and folded to form a unique three-dimensional structure. It also includes an area that is called”the active location” (Figure 1) in which the substrate actually bonds. The Active site could be comprised of just a tiny fraction (less than 10) of amino acids. It is the charge and shape property of the site active that allow it to be bound to a specific type of of the substrate molecule, which means that the enzyme can be in a position to show a significant degree of specificity to the substrate molecule, allowing it to demonstrate significant specificity in catalytic activity. Best NEET Coaching in Guwahati. They offer structure and protection for the multicellular organism’s body through hair, skin cartilage, callus, muscles, ligaments, and tendon. Proteins regulate and catalyze body’s chemistry, in the form of enzymes, hormones and immunoglobulins, etc.
The idea that the specificity of enzymes result from the complementarity of both the substrate as well as the activation site was initially suggested by the German scientist Emil Fischer in 1894, and The term was later referred to as Fischer’s “lock and key theory’ which requires only a key of the correct size is required.The shape (the shape of the substrate) can be inserted into the keyhole (the shape) fits into the keyhole (the active location) inside the lock (the enzyme). Itsamazing the idea of this theory came up in a time where it was still not confirmed that enzymes were proteins. The more information was uncovered about the structure of enzymes through methods likeby X-ray crystallography. was discovered that enzymes aren’t solid structures, but in realityextremely flexible in form. They offer structure and protection for the multicellular organism’s body through hair, skin cartilage, callus, muscles, ligaments, and tendon. Proteins regulate and catalyze body’s chemistry, in the form of enzymes, hormones and immunoglobulins, etc. Best NEET Coaching in Guwahati.
Based on this discovery, in 1958, Daniel Koshland extended Fischer’sconcepts and proposed the ‘induced-fit model of substrate and enzyme binding, where the The shape of the enzyme molecule is altered slightly to allow for the substrate’s binding. The An analogy that is often used is the ‘hands-in-glove’ model where the glove and the hand are. The shape is broadly similar in shape, however the glove is molded around the hand when it is placed intoIn order to make sure that you get the perfect for a perfect.Since it is only the active site that is able to bind to the substrate it makes sense to inquire what thefunction of the other protein role of the rest of the protein. The most straightforward reason is that it functions to stabilize the active site , and provides an ideal environment to allow interaction between the site and the substrate molecules.
Thus, the active site can’t be separated from the other protein. Without a loss of catalytic activity without loss of catalytic activity, even though laboratory-based directed (or forceful) evolution Studies have proven that it’s sometimes possible to create smaller enzymes, which do not retain activity. It is important to note that a significant portion of enzymes are composed of proteins,Some also contain non-protein components, also known as a cofactor. It is required to the enzyme’s catalytic function. Best NEET Coaching in Guwahati.Cofactors can be another organic molecule, in this the case it’s is referred to as a coenzyme or it may be an organic molecules, usually a metal or ion, such as manganese, iron as well as zinc, copper, and cobalt. A coenzyme that is able to bind tightly and permanently to protein is commonly is referred to as the prosthetic group of enzyme.
If an enzyme needs an additional cofactor to function the protein component that is inactive is commonly called an apoenzyme. one that is referred to as an apoenzyme and its cofactor (i.e. the active enzyme) is known as an homoenzyme. The requirement for vitamins and minerals in our diet is in part due to their functions within metabolism as cofactors as well as coenzymes. Reaction equilibrium and enzymes What is the function of enzymes? Best NEET Coaching in Guwahati.The general solution to the question lies in that they don’t affect the equilibrium (i.e. how thermodynamics work) of reactions. This is due to the fact that enzymes don’t fundamentally modify the structure and the energetics of the substances and reagents They do not change the energy and structure of the products or reagents, they just letthe equilibrium of reaction to be reached more quickly.
Therefore, let us begin by delving into the Concept that chemical equilibrium is a concept. In many instances, an equilibrium reaction is to the right, that is, nearly all of substrate (S) is transformed to product (P). This is why reactions are usually described as follows: This is a simplified version and, as with all situations, it is better to form this reaction in the following manner: This suggests the existence of equilibrium. To comprehend this concept, it might be helpful to consider it is extremely helpful to examine an event where you can see that the point of equilibrium central. For instance: Isomerase for Glucose Fructose and Glucose. In this reaction we begin with the solution of 1 mole L-1 Add the glucose and enzyme, and thenafter completion, the mixture will be of about 0.5 mg l-1, glucose and 0.5 mg L-1fructose.
It is also the equilibrium point in this specific reaction, and while it might be a bit sporadic, it is Take a couple of seconds to get to this point. If the enzyme is be able to reach this point with the enzyme present. In actually The same reaction would occur in the event that we put glucose into solution and waited for several months until the reaction took place in the absence of enzyme. It is interesting to note that we could start this reaction using 1 mol of l-1. Best NEET Coaching in Guwahati. The fructose solution could have been in the opposite direction. until the equilibrium point was attained. The equilibrium point of this reaction is expressed in an equilibrium constant, Keq follows: Substrate concentration near the end Substrate.
For an equilibrium to the left’, Keq should beSo, if a reaction is found to have an Keq value of 106, it is considered to be Keq. The equilibrium is away to the rightIt is possible to simplify it by describing it as an arrow with a single point. It is common to describe this kind of reaction as a single arrow. as “going to completion”. However, if a process is described as ‘going to completion’, it has the Keq value of 10-6, it means that the reaction is The equilibrium is quite quite a ways to the left and for all practical reasons, it is not considered to be the best way to go. It is worth noting that, even though the concentration of reactants does not have any effect on the equilibrium point environmental variables like pH and temperature may alter the position on the point of equilibrium. Best NEET Coaching in Guwahati.
It is also important to remember that any biochemical process that is observed in vivo in living systems is not a standalone event and is component of an metabolic pathway which makes it difficult to understand the connection between reactions and reactants. In vivo reactions aren’tallow them to move to their equilibrium point. If they did then, the reaction would be essentially stop (i.e. the reverse and forward reactions would be balanced) There is no net flux of the pathway. But, in many complicated biochemical pathways, there are some Individual reaction steps are near equilibrium, while others are further from equilibrium and theThe latter (catalysed by regulator enzymes) possessing the most ability to regulate the overall flux of materials along the route. Best Neet coaching in Dispur
Enzymes create complexes with their substrates The most common way to describe an enzyme-catalyzed reaction as undergoing three phases as the following: The ES complex is an area where the substrate (S) is attached by the enzyme (E) in which this reaction (whatever it may be) can be made more favorable. Best NEET Coaching in Guwahati. Once the reaction has been made favorable, it is immediately able to be improved. After the event has occurred that the molecule responsible for the product (P) has dissociated from the enzyme and can then be released to be bound to the enzyme. to another to another. In the course of this process , the substrate is changed to an intermediate form (often called the “transition state”) before transforming to the final product.
The precise mechanism by which the enzyme is able to speed up the speed of the reaction varies between systems. The general idea is that the binding process binds the substrate in an enzyme enzyme. This reaction that involves the substrate is made favorable by lowering the enzyme’s activity. Energy of activation for the reaction. In terms of energy reactions are either exergonic (releasing energy) or endogenous (consuming energy). But, even in an exergonic reaction that only consumes a small amount of energy is consumed. called the activation energy, is required to provide the reaction with an ‘acceleration kick-off. Best NEET Coaching in Guwahati.An analogy is the term “activation energy” which of matches of a match, the head of which contains an energy-rich mix of chemical compounds (phosphorus sesquisulfide, potassium chlorate and sesquisulfide).
If a match is burned, it releases significant quantities of the energy of light and heat (exergonically reacting with oxygen that is in the air). But, perhaps fortunately it is unlikely that a match will spark up in a flash, but an insignificant amount of energy in the form. The heat that is generated by friction (i.e. striking matches) is what triggers the reaction. Of Once the match is over, the energy released is enormous as well as significantly exceeds the tiny energy inputs much more than the tiny energy input. As illustrated in Figure 3.3, enzymes are believed to decrease the energy required to activate the system. through making it easier that the state transition can be formed. With the help of an enzyme catalyst it makes the process of forming the transition state becomes more energetically advantageous (i.e. it needs less energy is required for the ‘kick begin’), thereby accelerating the rate at which reaction can take place. Best NEET Coaching in Guwahati. H
Mechanisms and properties of enzymes Action Enzyme Kinetics involves the investigation of variables which determine the rate of reaction catalyzed by enzymes. It employs mathematical equations that may be confusing for students at first. They are the ones who come into contact with them. But the theory of the kinetics is both rational and easy to grasp, and it is vital to gain a better understanding of the subject to comprehend the importance of enzymes, both in metabolism and in biotechnology. Tests (measurements) for enzyme activities can be carried out either in a continuous or continuous fashion. Discontinuous methods involve mixing substrate and enzyme in a and measuring the result over a certain period of time, they are usually simple and easy to carry out.
It is generally recommended to make use of such assays in cases where we are not sure of the results Concerning the system (and we are conducting preliminary inquiries) or, alternatively, when we have information about that there is a There is a lot to know about the system, and we know a lot about the system and are confident that the period we have chosen is the best one. In continuous enzyme tests, we usually study the speed of an enzyme-catalyzed reaction is achieved by mix the substrate with enzyme and recording the appearance of the product as time passes. Naturally, we can as be able to measure the rate of the reaction by mixing the enzyme with substrate and continuously measuring its appearance. Best NEET Coaching in Guwahati.
A decrease and an increase) in which case, the two values will be the same. In experiments involving enzyme kinetics to make things easier, we often employ an artificial substrate known as an chromogen. It produces an intensely colored product, which makes the reaction easy to track with a colorimeter or the spectrophotometer. But, we can indeed use any analytical instrument that can produce the ability to produce brightly colored products. ability to determine the amount of concentration in either the substrate or the product. In the majority of cases, we’d also consider adding buffer solutions to the mix. We will learn more about this later. The activity of enzymes is greatly influenced by pH, which is why it is crucial to keep the pH at a particular level. and ensure it remains constant and keep it constant throughout the entire experiment.
The first experiment in enzyme kinetics could therefore involve mixing the solution of a substrate (chromogen) (chromogen) in the buffer solution, and then by adding the enzyme. This mixture will then be In a spectrophotometer, the color of the product would be determined. This will allow us to observe a quick reaction that, after a couple of minutes or seconds, It is possible that the pace of slowing down and slow down. Best NEET Coaching in Guwahati. The most common reason for this slowing of the rate (rate) that the process is because of The substrate in the mix is getting used up and is thereby limiting. It could also be that the It could be that the enzyme is unstable and denaturing throughout the test. The pH of the mix is changing as some reactions use or release protons. In this way whenever we have to determine the rate of reaction it is done early, immediately after the enzyme is added, and if no of the limitations above are in effect. The initial rate of rapidity as the velocity at which it began (v0). It is the measurement of the reaction.
The rate at this point is also fairly straightforward because the rate is linear. Therefore, we can Simply create a straight line, and take a measurement of the change in concentration (by dividing the change in concentration by the time period) to assess the rate of reaction over the time period. It is possible to now run several similar enzyme tests to determine how fast the initial velocity Changes occur when the substrate’s or enzyme concentration is changed or the pH is altered. These studies will assist us understand the characteristics of the enzyme we are studying. The relationship between the enzyme concentration and the rate of reaction is generally an Simple one. It is a simple one. as described above, but adding 10 percent more enzyme, the reaction is It will be 10 times faster when we increase the concentration of enzyme the reaction will run at a rate of twice as quickly. Best NEET Coaching in Guwahati.
So there is a clear linear relation between the rate of reaction and the amount enzyme that can catalyze this reaction. This applies to living enzymes and for those utilized in biotechnological processes, where controlling the amount of enzyme used can be used to regulate the reaction rates. When we run a number of enzyme tests using the same concentration of the enzyme, But with different concentrations of substrate and concentrations, a more complex relationship is revealed, as illustrated in Figure 6. At first in the case of substrate concentration is Increased, the rate reaction accelerates. As the concentration of the substrate increases further, the effects on the reaction rate begin to decrease as the reaction progresses until a certain stage has been reached.
At a point where increasing the concentration of substrate has no effect on reaction rate. At this point, the enzyme is believed to be close to saturation substrate, and showing its maximum speed (Vmax). It is important to note that this velocity is the maximum. is in reality a theoretical limit , which will never be attained in any experiment however, we could be very close to could be very close to. The equation discussed here is a typical one, and mathematics students might find interesting. Best NEET Coaching in Guwahati. It is immediately recognized as a rectangular hyperbola that is immediately identifiable as a rectangular. Its equation for describing this relationship is as the following: These two constants & b therefore allow us to define this hyperbolic relation, in the same way asby a linear relationship (y is mx plus C) that can be expressed using the 2 constants, m (theslope) and slope) and (the the intercept).
We’ve actually identified the constant a Vmax. This constant is small amount complex, since it is the value of the x-axis which yields half of the maximum value of the y. In enzymology, we refer to it as Michaelis constant (Km) and it is the concentration of the substrate which gives half-maximal velocity. The equation we come up with, which is commonly referred to as the Michaelis-Menten equation is Rate of initial reaction ( )= Substrate concentration Max Concentration of Substrate It was 1913 when Leonor Michaelis, along with Maud Menten first demonstrated that it was feasible to Calculate this equation mathematically using basic principles, based on basic assumptions regardingthe manner in how an enzyme reacts an ingredient to produce the product. Their origin lies in the idea that the reaction happens through creating an ES complex, which,When formed, it is able to after formation, dissociate (productively) to release the product the molecule, or dissociate from the reverse direction with no creation of the product. Best NEET Coaching in Guwahati.
The reaction could be described as is followed, with K1, K-1 and k2 representing the rate constants of the three reactions: The Michaelis-Menten formula is based on two assumptions. The primary assumption is that we’re evaluating the initial speed of the reaction (v0) at which point the concentration of the product is minimal (i.e. [S [P(i.e. [S] [P]) which means that we are able to ignore the possibility of any substance that is converting to substrate. The second hypothesis is that the amount of substrate is significantly higher than the amount of enzyme (i.e. [S] [E]). The formula begins with an equation to calculate that expression, the initial rate the rate of the process of forming a product by the rate of the ES complex breaks down to form of product, as the rate at which the ES complex dissociates to form.
Best NEET Coaching in Guwahati. This is based on the constant for the rate of change k2 along with the intensity of the ES complex as follows: Because ES can be described as an intermediary and its concentration is not known However, we can define it in terms of known of known. With a steady-state approach, it is possible to assume that, even though the amount of product and substrate changes but the concentration of the ES complex itself is constant. Best NEET Coaching in Guwahati. The rate at which the ES complex is formed the ES complex as well as the rate at which it breaks down will, consequently balance, where: owever, they do not fundamentally alter or affecting the level of energy of both the reactive agent and the product, but not fundamentally altering the energy levels of either. The rate of complex ES formation Ratio of ES complex breakdown = + ( ) 1 k 2 ES. Hence, at steady state. owever, they do not fundamentally alter or affecting the level of energy of both the reactive agent and the product, but not fundamentally altering the energy levels of either.
The equation can be modified to produce [ES] in the following manner: Because the amount of the substrate is much higher than the amount of enzyme (i.e. [S [E[S] [E) (the concentration of the uncombined substrate is nearly equivalent to the entire concentration of the substrate. The uncombined enzyme concentration [E] is equivalent to E’s total concentration less the concentration of substratum [ES]. Incorporating these terms and the process of solving for ES results in the following: This concept in Equation 1 to give: The word k2[E]T actually is Vmax, which is the speed at which you can travel the most. Therefore, Michaelis and Menten We were able deduce their equation in the form of: A more in-depth explanation of the Michaelis-Menten formula can be found in numerous Biochemistry books (see Section 4 of the Recommended Reading Section). There are also many very informative tutorials online available for the area. Best NEET Coaching in Guwahati.
Michaelis constants were identified for numerous enzymes commonly used and they are generally found in the upper millimolar region . It is worth noting that there are enzymes that catalyze the same reaction, but are made from Different organisms from different organisms, can have vastly different Km values of different organisms. Additionally, an enzyme that has many substrates could have diverse Km values for each substrate. Km values that are low Km value suggests that the enzyme only requires a the smallest amount of substrate in order to be in order to become. Thus, the highest velocity can be reached when the substrate is at relatively low concentrations. An extremely high Km value is a sign of the requirement for high levels of substrate in order to attain the highest to achieve the highest speed of reaction.In this way, we usually use the term Km as an indicator of the affinity of the enzyme towards its substrate, which is actually an inverse measurement, in which Km is the most high value. Km indicates low affinity for the enzyme, and vice versa. The Km value tells us a number of crucial facts about an enzyme.
A enzyme that has a low Km value in relation to the concentration in physiological substrate will Best NEET Coaching in Guwahati. Most likely to be always covered in substrate which is why it will act in a steady manner, regardless of changes in the amount of substrate in the range of physiological levels. A enzyme that has a high Km value in relation to the concentration in physiological substrate will The substrate will not be completely saturated Its activity will vary based on the amount of substrate present and the rate at which it forms product will be influenced by the quantity of substrate. substrate. 3. When an enzyme is active on a variety of substrates, the one with most Km value is often considered to be the enzyme’s “natural” substrate, but this could not be the case in 4. When two different proteins (with comparable Vmax) in distinct metabolic pathways are competing for the samesubstrate, and when we know the Km values of the two enzymes, then we can predict their ratio of the substrate.
The pathway with one enzyme has lowest Km The value will likely be the preferred pathway that is, more substrate will be able to flow through this pathway in the majority of circumstances. For instance the Phosphorufructokinase (PFK) is an enzyme responsible for forming PFK. catalyzes the initial step of the glycolytic pathway. This produces energy for the A form of ATP that is used by the cell, while the glucose-1-phosphate UIDYLYL TRANSFERASE (GUT) form of ATP for the cell.enzyme in the early stages of the process leading to process that leads to the synthesis and production of glycogen early in the pathway leading to the synthesis of (an energy storage molecules). Both enzymes employ monophosphates of hexose to form substrates, however their Km differs. The substrate is less than GUT’s substrate. its substrate. Therefore, at lower cellular hexose concentrations of phosphate, PFK will be active and GUT will be inactive. Best NEET Coaching in Guwahati.
The concentration of phosphate in both pathways will be in active. The cells will only retain phosphate concentrations. glycogen during times of abundance glycogen in times of abundance. Always give preference to the path of ATP production. that is the most important role. Often, it’s impossible to determine Km values from a simple graph of velocity against Substrat concentration (as illustrated on Figure 6) since we haven’t employed sufficient concentrations of substrate to even come close to estimating the maximum velocity which is why we have not been able to estimate maximal velocity.It is impossible to evaluate half-maximal velocity and, consequently, Km. Fortunately you can graph our experiments data in a different manner to get the numbers. The most widely used Alternative is the Lineweaver Burk plot (often called the double-reciprocal plot). The plot Linearizes the hyperbolic curve and produces a line that is simple to extrapolate.
Allowing the evaluation of Vmax permitting evaluation of Vmax Km. For instance that we only have the first seven values, we could evaluate Vmax and Km. In the points shown in Figure 6, we might have difficulty estimating Vmax using a plot directly as illustrated in But, as illustrated in Figure 7b, when those seven points were drawn on the graph of 1/velocity against the concentration of 1/substrate (i.e. an inverse-reciprocal graph) The data are linearized with respect to 1/substrate concentration. Best NEET Coaching in Guwahati. The line can easily be extended to the left to create an intercept on the y-axis as well as the x-axis, using where Vmax and Km are able to be analyzed. One of the major disadvantages using the lineweaver-burk plot is that it can be over-simpleinfluence it imparts to measurement results taken with the lowest concentration of substrate. The influence that it gives to measurements made at the lowest concentrations of substrate. Concentrations may be the most vulnerable to errors (due to the difficulty in making multipleDilutions) that result in reactions which, since they are slow, could be more susceptible to measurement error.
As is evident in the figure 8 measurement errors can be caused by points, when transformed on theLineweaver-Burk plots will have a major impact on the best fit calculated from the dataand, consequently, in the extrapolated value of and Vmax as well as Km. Both sets of points are shown inFigure 8 is the same with the exception of one point in the top left, which shows (because of theThe plot’s double-reciprocal nature) one point that is derived from the very low concentration of substrateand a lower and a slow reaction rate. But, one single factor could have a significant impact on the overallbest fit , and the associated estimates of Kinetic constants and their estimates. Best NEET Coaching in Guwahati.
The nature and classification of enzymes-Enzymes are biological catalysts (also known as biocatalysts) that speed up biochemical reactions
in living organisms. They can also be extracted from cells and then used to catalyse a wide range of commercially important processes. For example, they have important roles in the production of sweetening agents and the modification of antibiotics, they are used in washing powders and various cleaning products, and they play a key role in analytical devices and assays that have clinical, forensic and environmental applications. The word ‘enzyme’ was first used by the German physiologist Wilhelm Kühne in 1878, when he was describing the ability of yeast to produce alcohol from sugars, and it is derived from the Greek words en (meaning ‘within’) and zume (meaning ‘yeast’). Best NEET Coaching in Guwahati. In the late nineteenth century and early twentieth century, significant advances were made in the extraction, characterization and commercial exploitation of many enzymes, but it was not until the 1920s that enzymes were crystallized, revealing that catalytic activity is associated with protein molecules.
For the next 60 years or so it was believed that all enzymes were proteins, but in the 1980s it was found that some ribonucleic acid (RNA) molecules are also able to exert catalytic effects. These RNAs, which are called ribozymes, play an important role in gene expression. In the same decade, biochemists also developed the technology to generate antibodies that possess catalytic properties. These so-called ‘abzymes’ have significant potential both as novel industrial catalysts and in therapeutics. Notwithstanding these notable exceptions, much of classical enzymology, and the remainder of this essay, is focused on the proteins that possess catalytic activity. As catalysts, enzymes are only required in very low concentrations, and they speed up reactions without themselves being consumed during the reaction. Best NEET Coaching in Guwahati. We usually describe enzymes as being capable of catalysing the conversion of substrate molecules into product molecules as follows.
Enzymes are potent catalysts-The enormous catalytic activity of enzymes can perhaps best be expressed by a constant, kcat, that is variously referred to as the turnover rate, turnover frequency or turnover number. This constant represents the number of substrate molecules that can be converted to product by a single enzyme molecule per unit time (usually per minute or per second). Examples of turnover rate values are listed in Table 1. For example, a single molecule of carbonic anhydrase can catalyse the conversion of over half a million molecules of its substrates, carbon dioxide (CO2) and water (H2O), into the product, bicarbonate (HCO3−), every second—a truly remarkable achievement.
Enzymes are specific catalysts. As well as being highly potent catalysts, enzymes also possess remarkable specificity in that they generally catalyse the conversion of only one type (or at most a range of similar types) of substrate molecule into product molecules. Best NEET Coaching in Guwahati.
Some enzymes demonstrate group specificity. For example, alkaline phosphatase (an enzyme that is commonly encountered in first-year laboratory sessions on enzyme kinetics) can remove a phosphate group from a variety of substrates. Other enzymes demonstrate much higher specificity, which is described as absolute specificity. For example, glucose oxidase shows almost total specificity for its substrate, β-D-glucose, and virtually no activity with any other monosaccharides. As we shall see later, this specificity is of paramount importance in many analytical assays and devices (biosensors) that measure a specific substrate (e.g. glucose) in a complex mixture (e.g. a blood or urine sample). Enzyme names and classification Enzymes typically have common names (often called ‘trivial names’) which refer to the reaction
that they catalyse, with the suffix -ase (e.g. oxidase, dehydrogenase, carboxylase), although individual proteolytic enzymes generally have the suffix -in (e.g. trypsin, chymotrypsin, papain).
Often the trivial name also indicates the substrate on which the enzyme acts (e.g. glucose oxidase, alcohol dehydrogenase, pyruvate decarboxylase). However, some trivial names (e.g. invertase, diastase, catalase) provide little information about the substrate, the product or the reaction involved. Due to the growing complexity of and inconsistency in the naming of enzymes, the International Union of Biochemistry set up the Enzyme Commission to address this issue. Best NEET Coaching in Guwahati. The first Enzyme Commission Report was published in 1961, and provided a systematic approach to the naming of enzymes. The sixth edition, published in 1992, contained details of nearly 3 200 different enzymes, and supplements published annually have now extended this number to over 5 000. Within this system, all enzymes are described by a four-part Enzyme Commission (EC) number.
For example, the enzyme with the trivial name lactate dehydrogenase has the EC number 18.104.22.168, and is more correctly called l–lactate: NAD+ oxidoreductase. The first part of the EC number refers to the reaction that the enzyme catalyses (Table 2). The remaining digits have different meanings according to the nature of the reaction identified by the first digit. For example, within the oxidoreductase category, the second digit denotes the hydrogen donor (Table 3) and the third digit denotes the hydrogen acceptor (Table 4). Thus lactate dehydrogenase with the EC number 22.214.171.124 is an oxidoreductase (indicated by the first digit) with the alcohol group of the lactate molecule as the hydrogen donor (second digit) and NAD+ as the hydrogen acceptor (third digit), and is the 27th enzyme to be categorized within this group (fourth digit).Best NEET Coaching in Guwahati.
Enzyme structure and substrate binding Amino acid-based enzymes are globular proteins that range in size from less than 100 to more
than 2 000 amino acid residues. These amino acids can be arranged as one or more polypeptide chains that are folded and bent to form a specific three-dimensional structure, incorporating a small area known as the active site (Figure 1), where the substrate actually binds. The
active site may well involve only a small number (less than 10) of the constituent amino acids. It is the shape and charge properties of the active site that enable it to bind to a single type of substrate molecule, so that the enzyme is able to demonstrate considerable specificity in its catalytic activity. The hypothesis that enzyme specificity results from the complementary nature of the substrate and its active site was first proposed by the German chemist Emil Fischer in 1894, and became known as Fischer’s ‘lock and key hypothesis’, whereby only a key of the correct size and shape (the substrate) fits into the keyhole (the active site) of the lock (the enzyme).
It is astounding that this theory was proposed at a time when it was not even established that enzymes were proteins. As more was learned about enzyme structure through techniques such as X-ray crystallography, it became clear that enzymes are not rigid structures, but are in fact quite flexible in shape. Best NEET Coaching in Guwahati. In the light of this finding, in 1958 Daniel Koshland extended Fischer’s ideas and presented the ‘induced-fit model’ of substrate and enzyme binding, in which the enzyme molecule changes its shape slightly to accommodate the binding of the substrate. The analogy that is commonly used is the ‘hand-in-glove model’, where the hand and glove are broadly complementary in shape, but the glove is moulded around the hand as it is inserted inorder to provide a perfect match.
Since it is the active site alone that binds to the substrate, it is logical to ask what is the role of the rest of the protein molecule. The simple answer is that it acts to stabilize the active site and provide an appropriate environment for interaction of the site with the substrate molecule. Therefore the active site cannot be separated out from the rest of the protein without loss of catalytic activity, although laboratory-based directed (or forced) evolution studies have shown that it is sometimes possible to generate smaller enzymes that do retain activity. It should be noted that although a large number of enzymes consist solely of protein, many also contain a non-protein component, known as a cofactor, that is necessary for the enzyme’s catalytic activity. A cofactor may be another organic molecule, in which case it is called a coenzyme, or it may be an inorganic molecule, typically a metal ion such as iron, manganese, cobalt, copper or zinc. A coenzyme that binds tightly and permanently to the protein is generally referred to as the prosthetic group of the enzyme. Best NEET Coaching in Guwahati.
When an enzyme requires a cofactor for its activity, the inactive protein component is generally referred to as an apoenzyme, and the apoenzyme plus the cofactor (i.e. the active enzyme) is called a holoenzyme (Figure 2). The need for minerals and vitamins in the human diet is partly attributable to their roles within metabolism as cofactors and coenzymes. Enzymes and reaction equilibrium How do enzymes work? The broad answer to this question is that they do not alter the equilibrium (i.e. the thermodynamics) of a reaction. This is because enzymes do not fundamentally change the structure and energetics of the products and reagents, but rather they simply allow the reaction equilibrium to be attained more rapidly.Let us therefore begin by clarifying the concept of chemical equilibrium. In many cases the equilibrium of a reaction is far ‘to the right’—that is, virtually all of the substrate (S) is converted into product (P). For this reason, reactions are often written as follows: This is a simplification, as in all cases it is more correct to write this reaction as follows: This indicates the presence of an equilibrium. To understand this concept it is perhaps most helpful to look at a reaction where the equilibrium point is quite central.
For example: Glucose Fructose Glucose isomerase In this reaction, if we start with a solution of 1 mol l−1 glucose and add the enzyme, then upon completion we will have a mixture of approximately 0.5 mol l−1 glucose and 0.5 mol l−1 fructose. This is the equilibrium point of this particular reaction, and although it may only take a couple of seconds to reach this end point with the enzyme present, we would in fact come to the same point if we put glucose into solution and waited many months for the reaction to occur in the absence of the enzyme. Interestingly, we could also have started this reaction with a 1 mol l−1 fructose solution, and it would have proceeded in the opposite direction until the same equilibrium point had been reached. The equilibrium point for this reaction is expressed by the equilibrium constant Keq as follows: Keq Substrate concentration at end point Substrate concentration at end point. Best NEET Coaching in Guwahati. Thus for a reaction with central equilibrium, Keq = 1, for an equilibrium ‘to the right’ Keq It should be noted that although the concentration of reactants has no effect on the equilibrium point, environmental factors such as pH and temperature can and do affect the position of the equilibrium.