Effects of a set of alpha-ketoglutarate phosphoanalogues on the activity of alpha-ketoglutarate dehydrogenase (EC 1.2.4.2) complexes from E. coli and pigeon breast muscle, as well as on alpha-ketoglutarate dehydrogenase isolated from the pigeon breast muscle, have been studied. alpha-Ketoglutarate phosphoanalogues (succinyl phosphonate and its monomethyl ester) were found to be effective inhibitors of alpha-ketoglutarate oxidative decarboxylation, catalyzed by both muscle and bacterial alpha-ketoglutarate dehydrogenase complexes, as well as muscle alpha-ketoglutarate dehydrogenase. The ability of glutamate phosphoanalogues to inhibit alpha-ketoglutarate oxidative decarboxylation has been shown in E. coli extract and a model system.