Action of lodoacetate on Dehydrogenases and Alcoholic Fermentation

IT is well known that iodoacetate produces a complete inhibition of alcoholic fermentation in yeast and of lactic acid formation in muscle even in very dilute concentrations (M/3000 or less). Up to the present, however, its mode of action and the precise point at which it attacks the catalytic systems are unknown, for none of the enzymes which has been tested is inhibited by such low concentrations. In high concentrations (> M/20) iodoacetate is a general enzyme poison and inhibits almost every enzyme tested. In moderate concentrations (M/100), it has no action on most enzymes and has hitherto only been shown to inhibit aldehyde mutase¹ and glyoxalase (the latter by an action not on the enzyme but on its coenzyme glutathione). These systems, however, are not inhibited by M/3000 iodoacetate, so that we must seek elsewhere for an explanation of its action on fermentation and glycolysis.