Aspects of kinetic techniques in enzymology

This chapter discusses the aspects of kinetic techniques in enzymology. As a general rule, the complexities of analyzing transient kinetic measurements may be circumvented by careful choice of experimental design. The objective is to employ conditions, where possible, under which the transient follows an exponential time course (or the sum of a small number of exponentials). In this circumstance, the kinetic process can be described by a single parameter, a rate coefficient, which is independent of the amplitude of the transient. Perturbation methods, in which systems are displaced slightly from a pre-existing equilibrium position and monitored as they relax to the new equilibrium position, fortunately always generate exponential (or sum of exponential) progress curves. The more conventional kinetic method, in which reagents (e.g. enzymes and substrates) are mixed and the subsequent approach to equilibrium is followed by monitoring the concentration of reactants or products.