The enzymic decarboxylation of oxaloacetate

Abstract

ALTHOUGH oxaloacetate has an important role in cellular metabolism, no enzyme has been described which brings about a rapid decarboxylation of the acid. Breusch [1939] investigated a heat-stable component of mammalian tissue responsible for this decarboxylation but could not identify it with any known physiological agent. The rate of this decarboxylation is comparatively slow. In investigations on the utilization of CO2 by bacteria, Wood & Werkman [1938; 1940] postulated the reverse reaction, i.e. the carboxylation of pyruvate to form oxaloacetate. This reaction was represented as follows: C02+CH3. CO.COOH HOOC. CH2 . CO.COOH. Evans & Slotin [1940] have demonstrated the utilization of C02 with pigeon liver by the use of radioactive CO2. The mechanism suggested by them is essentially the Wood & Werkman reaction. Krebs & Eggleston [1940], also working with pigeon liver, suggested that the reaction occurs in the dissimilation of pyruvate. They postulate that aneurin is required in the fixation. Smyth [1940] came to the same conclusion using vitamin-deficient staphyl;ococci.