2-Oxoglutarate decarboxylase ofLeuconostoc oenos

InLeuconostoc oenos, the typical organism of the malolactic fermentation of wine, a 2-oxoglutarate decarboxylase was detected. This inducible enzyme decarboxylates 2-oxoglutarate but not pyruvate. The resulting succinaldehydate is rapidly reduced to 4-hydroxybutyrate or oxidized to succinate in further reactions. 2-Oxoglutarate decarboxylase is thiamin-diphosphate-dependent; the pH optimum is at 5.3 and theK m value for 2-oxoglutarate is 1.8 mmol/L.