Kinetics of irreversible enzyme inhibition by an unstable inhibitor.

Computer simulations of the irreversible inhibition of an enzyme by an unstable inhibitor are presented. Data obtained at the end point of reaction are shown to conform poorly in many situations with relationships derived from integrated rate equations by setting t = infinity, and the implications concerning the experimental use of this method to determine kinetic constants describing inactivation are considered. The alternative approach of conducting experiments under conditions of inhibitor excess over enzyme is further discussed, and a graphical procedure is suggested for the description of time courses of reaction of enzyme with unstable inhibitor when an enzyme-inhibitor adsorptive complex is involved.