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Chemistry of Enzyme catalysed Reactions
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Kcat/Km and Mechanism of Chymotrypsin

Ashish Kr Dwivedi
Former Scientist (IIT Kanpur), Authored 10+ Peer Reviewed International Publications, PhD (IITK) Chief Mentor Triyambak Life Sciences

U
Unacademy user
bhot confusion h sir ji 🙄🙄
sir m aap ke lacture ke sath path finder ki book padh rha hu kya itna materiyl sufficint hoga ya koi alag se or bhi padhu
  1. Basics of Biochemistry Reaction Mechanism of Enzymes Ashish Kr Dwivedi, PhD


  2. Amino acid General acid form (proton donor) General base form (proton acceptor) residues Glu, Asp Lys, Arg Cys R COOH R-COO R--NH R-NH2 R-SH R- S R-C CH His NH N: Ser R-OH R-O Tyr OH


  3. Enzyme Substrate K (mM) ATP D-Glucose D-Fructose Hexokinase (brain) 0.4 0.05 1.5 Carbonic anhydrase Chymotrypsin 26 108 Glycyltyrosinylglycine N-Benzoyltyrosinamide 2.5 Enzyme Catalase Carbonic anhydrase Acetylcholinesterase B-Lactamase Fumarase RecA protein (an ATPase) Substrate H,O , Acetylcholine Benzylpenicillin Fumarate ATP kcat (s-1) 40,000,000 400,000 14,000 2,000 800 0.5


  4. kcat/Km (M 1s-1) 1.6 108 8.3 107 1.5 1 7 4 107 2.8 108 1.6 108 3.6 X 107 1 X 108 cat Enzyme Acetylcholinesterase Carbonic anhydrase Substrate 9 10-5 1.2 10-2 2.6 X 10-2 1.1 100 Acetylcholine CO HCO3 H2O Crotonyl-CoA Fumarate Malate Benzylpenicillin 1.4 104 1 106 4 X 10s 4 107 5.7 103 8 102 9 102 2.0 X 103 Catalase Crotonase Fumarase 2 10-5 5 10-6 2.5 10-5 2 10-5 B-Lactamase


  5. Chymotrypsin (free enzyme) Asp 102-\ His 57 Ho--( Ser195 Hydrophobic pocket Active site Oxyanion holeHH 193 195 Gly Ser


  6. ES complex Asp 102)- His57 SHO -( Ser195 O R 193 195 Gly Ser


  7. ES complex 102 )- , C His 57 195 Ser O R' 193 195 Gly Ser


  8. Short-lived intermediate (acylation) Asp 102 His 57 o Ser15 C-CH NH-AA O R' 193 195 Gly Ser


  9. Acyl-enzyme intermediate Asp 102)- His 57 Ser 195 C-CHNH-AA 195 Gly 193 Ser