Determination of Michaelis Constants for - Lactamase Reaction by Spectrophotometric Methods

Abstract

Direct spectrophotometric assay of -lactamase activity toward cephalosporins was found readily applicable to penicillins too. The differential UV absorption spectra of various penicillins and their corresponding penicilloic acids were determined. The appropriate experimental conditions have been examined and the spectrophotometric assay seems adequate for the study of several substrates in a mixture. Moreover this method was found suitable for the computerized analysis of the kinetic data for the determination of Michaelis constants of the various penicillins. The use of the integrated form of the rate equation for the evaluation of the best estimates of Michaelis constants was found to be advantageous.