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Co enz
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- 2. Co-Enzymes Enzymes sometimes areconjugated proteins Enzyme (conjugated protein)=Apo-enzyme (inactive) The non-protein part = Co-enzyme Apo-enzyme + Co-enzyme=Holoenzyme (active)
- 3. Apo-Enzyme and Co-Enzyme Someenzymes have two parts The protein part is called Apoenzyme The non-protein part is called Co- enzyme When tightly bound the Co-enzyme is called Prosthetic-Group
- 4. Classification of Co-Enzymes Coenzymescan be classified by two ways ( I ) Classification based on functional characteristics (II ) Classification based on structure
- 5. (I) Classification basedon functional characteristics A. Transfer of group other than H 1. Sugar Phosphates 2. Thiamine pyro-phosphates 3. Pyridoxal Phosphate 4. Folate co-enzyme 5. Co-enzyme A 6.Biotin 7.Cobamide co-enzyme B12 8.Lipoic Acid
- 6. B. Transfer ofH+ group 1. NAD+ , NADP+ 2. FMN , FAD 3 LIPOIC ACID 4.C0-ENZYME Q
- 7. (II) Classification basedon structure Presence of Adenine ring joined to Ribose Many Co-enzymes may therefore be regarded as derivatives of Adenosine mono phosphate .They are:-
- 8. Co-enzymes as AdenosineDerivatives 1. Active Methionine 2.Amino Acid Adenylate 3.Active Sulphate 4. 3’ 5’ Cyclic AMP 5. NAD, NADP 6. FAD 7.Co.A
- 9. Characteristics Of Co-Enzymes Co-Enzymes are :- Thermo stable Dialyzable Non- colloidal Non-protein Are altered at the end of a reaction and sometimes may be changed They usually belong to the Vitamin ‘B’ complex group
- 10. Co-Enzyme Vitamin Derivative Enzyme Requiring TPP Co-Decarboxylase VitaminB1 Thiamine Pyruvate Dehydrogenase α.Keto Glutarate Dehydrogenase Transketolase FAD FMN Vitamin B2 (Riboflavin) D-amino acid Oxidase L-amino acid Oxidase Pyridoxal PO4 Co-Transaminase Vitamin B6 Pyridoxine Transaminase
- 11. Co-Enzyme Vitamin Derivative Enzyme Requiring Co-Enzyme A Co-Acylase Vitamin PantothenicAcid Thiokinases Thiolases NAD+ NADP+ Vitamin Nicotinic Acid LDH,Alcohol Dehydrogenase G-6-P Dehydrogenase Tetra Hydro Folate (FH4) Folic acid One Carbon Transfers Thymidilate Synthase Serine Trans Hydroxy methylase Cobamide Co-enzyme Vitamin B12 Homocysteine methyl Transferase
- 12. Co-Enzyme Vitamin Derivative Enzyme Requiring Biotin Co-Carboxylase Vitamin Biotin Acetyl CoA Carboxylase Pyru:Carboxylase Ubiquinone NADH Dehydrogenase Cytochrome b Heme Co-enzyme - Peroxidase Catalase Cytochrome
- 13. Function of Co-enzymes Theyaccept atom or group from a substrate and transfer it to the other molecule. Eg: Transaminases R─NH2 + R1─ C ═ O + PyPO4 PyPO4─NH2 R1─ NH2 + R─ C═ O + PyPO4
- 14. NAD and NADPact as hydrogen acceptors in dehydrogenating reactions T.P.P functions in oxidative decarboxylations. CoA in Acyl group carrier Tetrahydrofolate as formate carrier in the synthesis of Purines and Pyrimidines.
- 15. PROENZYMES Some enzymes, particularly theProteolytic enzyme , may be secreted as inactive proenzymes or zymogen.
- 16. At theactive site ,one or more specific covalent peptide bonds of each such pro- enzymes are hydrolyzed either enzymatically or by pH changes to yield the active enzyme and some inactive peptides called masking substances Hydrolysis makes the active site of the enzyme free and available to catalytic action.
- 17. PROENZYME ACTIVATOR PRODUCTS Pro- Enzyme ActivatorActive Enzyme Masking Substances Pepsinogen HCl or Pepsin Pepsin Inactive peptide Trypsinoge n Enterokina se Trypsin Inactive Hexapeptide Chymotryps inogen Trypsin,Ch ymotrypsin α- Chymotrpsin α-Inactive Peptide
- 18. PROENZYME ACTIVATOR PRODUCTS Pro-EnzymeActivator Active Enzyme Masking Substances Pro- Carboxypept idase A Trypsin Carboxype ptidase A Inactive Peptide Prothrombin Prothromb inase Thrombin Inactive polypeptide Pro- Fibrinolysine Fibrino lyso Kinase Fibrino Lysine Inactive Peptide