The substrate analog bromopyruvate as a substrate, an inhibitor and an alkylating agent of malic enzyme of pigeon liver

Bromopyruvate is an alkylating agent of pigeon liver malic enzyme (malate dehydrogenase (decarboxylating), EC 1.1.1.40). It combines first with the enzyme to give an enzyme-bromopyruvate complex, then reacts with a proximal -SH group, resulting in the formation of a pyruvate derivative. Bromopyruvate is also a substrate for the reductase partial reaction, and a non-competitive inhibitor of L-malate in the overall oxidative decarboxylase reaction catalyzed by this enzyme. Modification of the -SH group by this compound is accompanied by concomitant loss of both oxidative decarboxylase activity and reductase activity on bromopyruvate. Inactivation of the overall activity is partially prevented by NADP+ or NADPH, singly or in combination with L-malate.