 This enzyme selectively catalyzed the decarboxylation of oxaloacetate to pyruvate and CO2 with a Km of 2.1mM, Vmax of 158 umol, and kcat of 311 s^-1.Mn2+ was required for enzymatic activity with a Km of 1.2mM for Mn2+.A oxaloacetate decarboxylase found in mitochondria and soluble cytoplasm was isolated and purified from rat liver cells in 1974 by Wojtcak et al.