Kinetic analysis of inhibitor actions on enzymes

Abstract

A set of data on a given peroxidase inhibition by quecertin, showing an unusually high experimental error, was used to demonstrate how data, seemingly unsuitable for graphical analysis, may still provide useful information on the inhibition mechanism. The most reliable model turned out to be a mixed non-competitive inhibition. The present statistical procedure has proved (i) to be a simple, general and unequivocal way to carry on kinetic analysis of enzymatic reactions under inhibition action, based only on consecutive linear regressions (no previous assumption about the inhibition mechanism is required); (ii) that experimental errors can play an essential role on the final decision about the inhibition mechanism and (iii) to be able to show how close to the Michaelis-Menten mechanism the kinetic model actually is. Therefore all proposed inhibition mechanisms were subjected to statistical judgement.