Identity of lactic and malic dehydrogenases

Abstract

The lactic and malic dehydrogenases in pigeon''s breast muscle were studied by Thunberg''s technique. Oxaloacetic acid inhibited both dehydrogenases: pyruvic acid only lactic dehydrogenase. The rates of lactic and malic dehydrogenation were about equal if optimum substrate concentrations were used (lactic > malic) and the oxidation products removed. The enzymes were not separated by kaolin. Arsenious acid inhibited both, fluoride only lactic. The enzymes were considered to be identical. Cozymase activated the enzyme.