CONTACT US: Contact info
|
Citation |
Tan AK, Fink AL. Biochem. J. 1992; 281 ( Pt 1)(Pt 1): 191-196. |
|
Copyright |
(Copyright © 1992, The Biochemical Society, Publisher Portland Press) |
|
DOI |
|
PMID |
1731755 |
|
PMCID |
|
|
Abstract |
Nafcillin was shown to reversibly inhibit beta-lactamase from Staphylococcus aureus PC1 with characteristics indicative of a type A inhibitor [Citri, Samuni & Zyk (1976) Proc. Natl. Acad. Sci. U.S.A. 73, 1048-1052]. At nafcillin concentrations above 80 mM, complete inactivation occurred within 200 s. Upon removal of the excess nafcillin the inhibited enzyme was re-activated completely, with a rate constant of 2.0 x 10(-3) s-1 (25 degrees C). The inhibited enzyme was shown to be in the form of a covalent acyl-enzyme intermediate. Digestion by pepsin and trypsin yielded a single nafcillin-labelled peptide fragment which was isolated, sequenced and shown to be: Ala-Tyr-Ala-Ser-Thr-Ser-Lys. This sequence corresponds to the region surrounding the active-site serine residue, Ser-70, indicating that the inhibitor is covalently attached to the same residue as productive substrates. Language: en |
|
Keywords |
beta-Lactamase Inhibitors; beta-Lactamases; Binding Sites; Chromatography, High Pressure Liquid; Enzyme Activation; Kinetics; Models, Theoretical; Nafcillin; Penicillin G; Peptide Fragments; Staphylococcus aureus |