PURIFICATION AND PROPERTIES OF OXALOACETATE DECARBOXYLASE FROM CORYNEBACTERIUM-GLUTAMICUM

Oxaloacetate (OAA) decarboxylase (E.C. 4.1.1.3) was isolated from Corynebacterium glutamicum. In five steps the enzyme was purified 300-fold to apparent homogeneity. The molecular mass estimated by gel filtration was 118 +/- 6 kDa. SDS-PAGE showed a single subunit of 31.7 KDa, indicating an alpha(4) subunit structure for the native enzyme. The enzyme catalyzed the decarboxylation of OAA to pyruvate and CO2, but no other alpha-ketoacids were used as substrate. The cation Mn2+ was required for full activity, but could be substituted by Mg2+, Co2+, Ni2+ and Ca2+. Monovalent ions like Na+, K+ or NH4+ were not required for activity. The enzyme was inhibited by CU2+, Zn2+, ADP, coenzyme A and succinate. Avidin did not inhibit the enzyme activity, indicating that biotin is not involved in decarboxylation of OAA. Analysis of the kinetic properties revealed a K-m for OAA of 2.1 mM and a K-m of 1.2 mM for Mn2+. The V-max was 158 mu mol of OAA converted per min per mg of protein, which corresponds to an apparent k(cat) of 311 s(-1).