Bromopyruvate, a potential affinity label for octopine dehydrogenase

Bromopyruvate, an analogue of pyruvate, one of the substrates of octopine dehydrogenase, was tested as an inhibitor of the enzyme. Provided both the coenzyme and the second substrate, arginine, were present, bromopyruvate rapidly inactivated the enzyme. This inactivation was irreversible, obeyed pseudo-first order kinetics and exhibited a rate saturation effect. Pyruvate protected the enzyme against inactivation by bromopyruvate and these compounds competed for the same site. Bromopyruvate also behaved as a true substrate for the enzyme. This reagent thus exhibits the kinetic characteristics of a good affinity label for octopine dehydrogenase.