How specific is the effect of penicillins on the conformation of penicillinase? An experimental model

The specificity of enzymes may ultimately depend on the conformational adaptability of the active site. Evidence supporting this view is provided by unusually sensitive tests based on the hysteretic kinetics of the penicillinase reaction. Parameters derived from such kinetics show that a unique conformation is induced in the enzyme by each of several closely related substrates. Similar differences in conformation can be deduced from rates of inactivation of penicillinase at saturating levels of such substrates.