Citation

Casas JL, García-Cánovas F, Tudela J, Acosta M. Journal of Enzyme Inhibition 1993; 7(1): 1-14.

Copyright

(Copyright © 1993)

DOI

10.3109/14756369309020183

PMID

7510789

Abstract

This paper deals with the development of an experimental method for the kinetic study of the inactivation of an enzyme by a racemic mixture of an inhibitor, whose isomers operate as suicide substrate and irreversible inhibitor respectively. The ratio between the isomer concentration in the biological or commercial source must be determined, but no separation of them is required. The method involves a kinetic analysis and an experimental design that enables the affinity (1/Km), rate of catalysis (kcat), rate of inactivation (lambda max), efficiency of catalysis (kcat/Km) and efficiency of inactivation (lambda max/Km) to be determined. The method has been applied to the kinetic characterization of the inactivation of 1-aminocyclopropane-1-carboxylate (ACC) synthase from tomato fruits by its substrate, S-adenosylmethionine (AdoMet). The ratio between AdoMet isomers with respect to its sulfonium centre, namely (-)-AdoMet and (+)-AdoMet, present in the commercial sample used, has been determined by 1H nuclear magnetic resonance.

Language: en

Keywords

Kinetics; Lyases; S-Adenosylmethionine; Substrate Specificity; Vegetables