Malolactic activity from Leuconostoc oenos ML34 is tightly associated with lactic dehydrogenase. A simple and fast procedure, involving affinity chromatography on agarose-hexane-NAD (Agnad), was used to separate malolactic activity from lactic dehydrogenase and other proteins. The yield was ca. 86%, the purification was 5.2-fold, and the K(m) values for l-malate, NAD and Mn were 2.8, 0.13, and 0.028 mM, respectively, at a pH optimum of 5.8.