Estimation of l-malate and fumarate by malic decarboxylase of Lactobacillus arabinosus

The manometric estimation of L-malate by the malic decarboxylase of Lactobacillu8 arabinosu8 17-5, has been described by As both the bacterial suspensions and the acetone powder extracts used by these workers have fumarase activity, the method measures the sum of malate and fumarate. In the present work, a modification is described whereby L-malate and fumarate are measured separately, and improvements are introduced which are based on the finding that in intact cells the activity of malic decarboxylase is optimal in the presence of glucose, manganous chloride and potassium chloride (Nossal, 1951b). Part of this work has been communicated to the Biochemical Society (Nossal, 1951a).