Properties of lactate dehydrogenase in a psychrophilic marine bacterium

Abstract

Lactate dehydrogenase (EC 1.1.1.27) from Vibrio marinus MP-1 was purified 15-fold and ammonium activated. The optimum pH for pyruvate reduction was 7.4. Maximum lactate dehydrogenase activity occurred at 10 to 15°C, and none occurred at 40°C. The crude-extract enzyme was stable between 15 and 20°C and lost 50% of its activity after 60 min at 45° C. The partially purified enzyme was stable between 8 and 15°C and lost 50% of its activity after 60 min at 30°C. The thermal stability of lactate dehydrogenase was increased by mercaptoethanol, with 50% remaining activity at 42°C.