title: Penicillin acylase and O-aryloxycarbonyl hydroxamates: Two acyl-enzymes, one leading to hydrolysis, the other to inactivation.
abstract: O-Aryloxycarbonyl hydroxamates have previously been shown to covalently inactivate serine/amine amidohydrolases such as class C β-lactamases and a N-terminal hydrolase, the proteasome. We report here reactions between O-aryloxycarbonyl hydroxamates and another N-terminal hydrolase, penicillin acylase. O-Aryloxycarbonyl hydroxamates, as non-symmetric carbonates, have two different leaving groups attached to the reactive central carbonyl group. We propose that these compounds can bind to the active site in either of two orientations and that either leaving group can be displaced from either orientation. In the present case we detected from kinetics experiments two distinct acyl-enzymes, one of which is subject to normal hydrolysis and the other to inactivation. Non-symmetric carbonates therefore can be very versatile enzyme inactivators.
authors.affiliation: Department of Chemistry, Wesleyan University, Middletown, CT 06459, USA.
authors.forename: S A
authors.initials: SA
authors.lastname: Adediran
authors.affiliation: Department of Chemistry, Wesleyan University, Middletown, CT 06459, USA. Electronic address: rpratt@wesleyan.edu.
authors.forename: R F
authors.initials: RF
authors.lastname: Pratt
mesh_terms: D020134:Catalytic Domain; D003432:Cross-Linking Reagents / Q000737:chemistry; D004791:Enzyme Inhibitors / Q000737:chemistry*; D004926:Escherichia coli / Q000201:enzymology; D006863:Hydrogen-Ion Concentration; D006868:Hydrolysis; D006877:Hydroxamic Acids / Q000737:chemistry*; D007700:Kinetics; D010399:Penicillin Amidase / Q000737:chemistry*; D046988:Proteasome Endopeptidase Complex / Q000737:chemistry; D000072417:Protein Domains; D012694:Serine / Q000737:chemistry; D013696:Temperature; D001618:beta-Lactamases / Q000737:chemistry
chemical_list: D003432:Cross-Linking Reagents; D004791:Enzyme Inhibitors; D006877:Hydroxamic Acids; D012694:Serine; D046988:Proteasome Endopeptidase Complex; D010399:Penicillin Amidase; D001618:beta-Lactamases
keywords: Enzyme inactivation; Enzyme kinetics; Enzyme mechanism; N-terminal hydrolase; O-Aryloxycarbonyl hydroxamates; Penicillin acylase