title: Evidence for the involvement of arginyl residue at the active site of penicillin G acylase from Kluyvera citrophila.
abstract: Penicillin G acylase (PGA) is used for the commercial production of semi-synthetic penicillins. It hydrolyses the amide bond in penicillin producing 6-aminopenicillanic acid and phenylacetate. 6-Aminopenicillanic acid, having the beta-lactam nucleus, is the parent compound for all semi-synthetic penicillins. Penicillin G acylase from Kluyvera citrophila was purified and chemically modified to identify the role of arginine in catalysis. Modification with 20 mM phenylglyoxal and 50 mM 2,3-butanedione resulted in 82% and 78% inactivation, respectively. Inactivation was prevented by protection with benzylpenicillin or phenylacetate at 50 mM. The reaction followed psuedo-first order kinetics and the inactivation kinetics (V(max), K(m), and k(cat)) of native and modified enzyme indicates the essentiality of arginyl residue in catalysis.
authors.affiliation: Division of Biochemical Sciences, National Chemical Laboratory, Pune 411008, India.
authors.forename: R Suresh
authors.initials: RS
authors.lastname: Kumar
authors.forename: C G
authors.initials: CG
authors.lastname: Suresh
authors.forename: Archana
authors.initials: A
authors.lastname: Pundle
authors.forename: Asmita
authors.initials: A
authors.lastname: Prabhune
mesh_terms: D019943:Amino Acid Substitution; D001120:Arginine / Q000032:analysis / Q000737:chemistry*; D001665:Binding Sites; D002384:Catalysis; D004789:Enzyme Activation; D007700:Kinetics; D044086:Kluyvera / Q000201:enzymology*; D010399:Penicillin Amidase / Q000032:analysis* / Q000737:chemistry*; D011485:Protein Binding; D013329:Structure-Activity Relationship
chemical_list: D001120:Arginine; D010399:Penicillin Amidase