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 Km for OAA of 2.1 mM and a Km of 1.2 mM for Mn2+. The Vmax was 158 mumol of OAA converted per min per mg of protein, which corresponds to an apparent kcat of 311 s-1.
Jetten
M S
MS
Department of Microbiology and Enzymology, Kluyver Laboratory for Biotechnology, Delft University of Technology, The Netherlands.
Sinskey
A J
AJ
D002262:Carboxy-Lyases / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D002412:Cations / Q000378:metabolism; D003352:Corynebacterium / Q000201:enzymology*; D004591:Electrophoresis, Polyacrylamide Gel; D007700:Kinetics; D008345:Manganese / Q000378:metabolism; D008970:Molecular Weight; D011770:Pyruvate Kinase / Q000378:metabolism; D013379:Substrate Specificity
D002412:Cations; D008345:Manganese; D011770:Pyruvate Kinase; D002262:Carboxy-Lyases; C021916:oxaloacetate decarboxylase