Lactate dehydrogenase in extracts of the foot muscle of the giant African snail Achatina achatina was found to be a d(−)-lactate-specific tetramer with a molecular weight of 139,000 ± 2000, and a subunit molecular weight of 35,000 ± 2000 was calculated for the predominant isoenzyme from its electrophoretic behaviour.2.2. The purified major isoenzyme showed optimal activity at pH 6.4–6.6 in the direction of lactate production but at pH 9.0 in the direction of pyruvate production.3.3. The Michaelis constants for pyruvate, d(−)-lactate, NADH and NAD+ were calculated to be 0.412, 2.130, 0.001 and 0.025 mM respectively.4.4. High concentrations of pyruvate () inhibited the enzyme whereas 200 mM dl-lactate did not.
Comparative biochemistry and physiology. B, Comparative biochemistry 12/1983; 75(2):263-268. DOI:10.1016/0305-0491(83)90325-5