Anabolic and Catabolic Pathway

UNIT-C ec-10 Cept of Metabolism : (Anabelic and catabolic pathway. Colic pathway:- anabolic pathway on anabolism is the set of structive process where the energy released by etabolism is used to synthesize complex molecule. Anabolism τηνolves threee basic stages (2) The production of precenssong such as amino acids, monosaccharides, nucleotides, etc. (2) Activation of these substance by using energy From ATP (3) The assembly of these precuressores ionto complese molecule such as proteins, polysaccharides, lipids, Nucleic acids, etc. Some important anabolic pathway are as follows (1) Carbon fixation:- →photosynthesis is the synthesis of carbohydrates From Hop and co₂ in the presence of sutilight ing Chlorophyll containing organisms. →9+ is performed by all living green plants, Cyanobacteria and some photosynthetic bacteria (2) carbohydrate anabolic pathway :- →on Carbohydrate anabolism simple organic acid's Can be converted into monosaccharides. These. Compound monosaccharides then used to assembly to foran polysaccharides such as starich (glycogen) Amino acid and protein synthesis:- →proteins are synthesized from amino acids Which are joined togethere in a chain of peptide bond in the ribosome which mainly takes place in the 4) Nudestide and Nucleic acid syothesis:- →Nucleotides are formed from pentosie and pyrimidine and phosphoric acids. Segare, → These nucleotides by polynucleotidie chain to Fornit ( nadeic acids of eithere RNA ore DNA Catabolic pathway:- catabolic pathway or catabolison is the pathway that breakdown lange molecules into simple Forums. →The purpose of the catabolic pathway is to provide energy and components needed by anabolic reaction. →The most common. Sets of catabolic pathway involves Following steps (1) Lange organic molecules such as proteins, polysaccha- rcides on lipids are digested into smaller components (2) These smallen molecules are taken up by cells and converted to smaller molecules Gually acetyl CoA The acetyl groups is oxidised to water and Coz in the TCA cycle and ETS to release energy Some of the important catabolic pathway (1) Digestion:- >Starch, Cellulose, proteins ante brokendown into smaller units in the presence of digestive enzymes → Starren in the presence of proteases digested. to amino acids similarly lipids in the presence Lipase digested to fatty acid and glycerid. →The end products like glircoso. amino acide Cortese akbehyltrate catabolic pathway:- is the breakdown of carbohydrates into smallere anit (monosaccharides) these monosaccharides such as glucose, fructose are converted into pyruvate and some ATPes generated by phosphorylation. pyruvate & an intermecliate in several metabollic pathway which is converted into acetyl CoA. through org dative decarboxylation which enter into TCA Cycle →ATP is generated in the TRA Cycle, (3) Fat catabolic pathway! Fats are catabolised by hydrolysts to three fatty acids and glycerol The glycerol enters glycolysis and fatty acids are broken down by B-oxidation to release acetyl cot which enter into TCA cycle and release energy (4) proteins and amino acld catabolic pathway :- →proteins are degraded to aminoacids enzymatically Armino acids oxidised to urea and 102. The oxiolation starts with the removal oft amino groces by transaminase. The amino group form the uncea These two reactions are called metabollite Pathway Regulation of metabolic spathway: Can be regulated by Changing the Some enzymes existing enzyme Changing Changing the activity of pre-existing enzyluk. The quickest way to Modulate the activity of an enzyme ome to alter the activity of an enzyme that already exingt the cell There are as- -LAR (I) substrate availability:- → Substrates binels to enzyme with a characteristic affinity called units of Molarity (KM) of the concent of a Substrate in a cell is much less than the km the activity of enzyme is very lon →of the substrcate concentration is much greater than Km the enzyme active site is saturcatoy with the substrate and the enzyme activity is More.. (Ⅱ) product inhibition:- off the product of a reaction is present in high Concentration of Wackled be energetically advantageous to the cell, if no more product was synthesized. This allows the whole pathway to be inhibited. Allostercic regulation:- As the many pathways are interconnectece it would be optimal of the Molecules of one pathway affected the activity of enzymes in another pathway also at fated. Molecules that bird to sites on target enzymes other than the active site (allosternic site) regulate the activity of tonget enzyme (IV) pt and enzyme conformation:- →Changes in plt which can accompany Metabolic process such as respiration can alter the Conformation an enzyme and enzyme activity. Changing the ammount of an enzyme 9- Another method to Modulate the activiteit enzyme is to attere the exnation τη transcription of enzymes gene:- enzyme four hormones can active ore inhibit of the transcription (2) year's the gene for a protein enzyme, gradation of Messenger RNA for the enzyne RNA For a protein cuid directly determine the ammount that protein synthesized small chhibitere RNA derci ved Com micro RNA can bind to specifte sequence on the RNA of a target enegue that affect the translation. of regulatory enzymes:--[LQ] regulatory enzyme which regulates the activity of Chemical pathway Regulatory enzymes exist at high concentration & that their activity can be increased on decreaseel with change In sustrate concentration. Some of the regulatory enzymes are as (1) Allosterric enzyme:- → This type of enzymes present two binding sites i.e. the substrate binding site or active site and the allostercic site or effecten binding site →The effecters are small molecules which modulate the enzyme activity → When the effecters molecules are bound to the allosteric site they lower the activity of enzyme →They do not participate as Catalyst directly but they are still essential properties:- →Alosteric enzymes are generally larger in mass than other enzymes →They are composed of multiple subunit which cont active sites and regulatory moleer (1) Homotropic allosteric enzyme :- on this type substrate and effector play a part sphory the modulation of the enzyme, which affects the en the #catalytic activity (I) (2) Heterotropic allostenic anzyne: - 9n this type of enzy > only the effecter performs the role of modulation Covalently Modulated enzymes! a Here the active and inactive form of the enzymes are t altered due to covalent modification of their structure is I which is catalized by the other enzynes • This type of regulation consists of the addition ore (Ⅱ) elimination of some molecules Which can be attached to the enzyme protein. ( The most remarkable covalent modification is phosphory. + Lation a phosphorylation: phosphorylation is the addition of phosphate groups to proteins which is the most frequent tegulatory modification mechanism in the cell- →phosphorylation has an lot of importance in regulatory. → pathway in cells. Ex. The acdition of a phosphoryl group (po) to an enzyme is catalized by Kinase enzyme while the I elimination of this group is catalizal by phosphate enzyme. →phosphorylation changes the conformation of an enzyne to a more active on inactive ways. Each phosphate group conturn tovo negetive charge. So that addition of this group can cause on the important change in Conformation of the enzyme osphorylation modifies the affinity of the the substrate enzyme Isozymes:- of enzgeso enzymes are the enzymes that differ in amino acid requence but catalize the same chemical reaction These enzymes have usually different regulatory propen- ties. The existance of isozymes permittes the fine tuning of Metabolism to meet the particulate needs of a given tissue Isazymes were first described by Huntere and Mankent who defined them as different variants of the same enzyme having identital Function and present in the same individual. EX: An Isoenzyme is glucokinase a variant of hexokinase which is not chhibited by glucose 6-phosphatt 9ts different regulatory features and lower affinity for glucose allow it to serve different function in cells of specific organs such as control of Insulin on initiation of glycogen synthests by liver cell. Carbohydrate metabolism:= (synthesis and catabolism of sucrose and statech):= Synthesis and catabolism of Jectiose:< → Sucrose is a disaccharide and commonly known as table sugar or cane sugar or beet sugar → at is the predominant form of segare and an organic Solute which is transport in plants From the leaves to different organ ot contains tovo simple sugar units i.e. glucose and fructose- and 99+ is abudandly present in ripened truits tike Mango, apple, pine apple, banana, ete. It is alo in venetre deles Dike cose 1-ph. + Fructose Sucrose phosphorylase sucrose +Pi neel Ey the enzyme recriose synthetase:- = ax otidin sucrose synthetase form Suenose in highere plants. diphosphate glucose and fructose in the presence Urculi'n diphosphate glucose & Fructose Sucrose synthetase sucrose & Umuiden di phosphate GI) By sucrose 6 ph. synthetase and phosphatate- Uridin diphosphate glucose and fructose 6-phosphate in the presence of the enzyme sucrose 6-phosphate synthe- tase to form sucrose phosphate and utridin diphosphate. Ucidindiphosphate greco se + fructose 6 ph. Synthetare Stecnose phosphate + Urielin di phosphate Sucrose phosphate produced is hydrolysed in the presence of an enzyme phosphatase to produce sucrose and inorganic phosphate. Sacrose phosphate +20 phosphatase → Slectrose +pp Catabolism of sucrose :- →Sucrose is catabolized by hychnolysis to form glucose and fructose in the presence of enzyme invertase on Suerase- → Thes the sucriose is hydrolysed to produce two monosaccharide cenits glucose and fructose. → Glucose and Fructose arre easily utilized by the plant cells fore various activities. Glucose directly entere respiratory process and Synthesis and catabolism of starich:- →Starch synthesis occcences within the chloroplast starcch is a storage homopolysaccharides in highere plants at contains a repeated units of glucose units Joined by 1.4 -gly cocidle bond in amylose and 1,6-gly cocidle bord in amylopection. Thus the statech Consists of an amylose and an amylopectin Chain → Amylose is a tinear polysaccharide while amylopee- tin is a branched poly saccharide →Starch acts as the most important reserve food material and stoerted form of energy in higher plants. →Syathesis of starch invaves the simultaneous synthesis of an amylose and an amylo pectin Synthesis of amglose:- → Syrahosis of amylose takes place by following steps (I) According to Hanes amylose can be synthesized in the presence of enzyme stanch phosphorylase From que cose 1-phosphate and an acceptere molecule consisting of about 3-20 glucose units joined by 1.4-glycosidic linkage. Starch Gile cose 1 - phosphate & Acceptere phosphorylar Amylose +P; mmation of 1,4-glycosidic linkage may also takes ace in the presence of the enzyme transglycosylase the transfere of glucose from unielin diphosphate lucose to an accepten molecule. din diphosphoglucose + Accepter Trans glyco 1 A glycosyl Sylase acceptere According to Akazawa glucose is trans Ferred to unidin diphosphate to fotem urridin diphosphate glucose From urtadin diphosphate glucose the glucose molecule is transferred to starch. 2-1,4 linkage Synthesis of Amylopectin:- →9n this process a donore molecule joined together by 1,4-glycocidte linkage is linked to an accepter Molecule which also contain 1,4-glycosidic linkage in the presence of an 8-enzyme. →The donore and the acceptere are linked by 1,6- glycocidic bond between & of the terminal glucose unit of donok molecule and Co of one of the glucose unit of the acceptere molecule.