[Properties of free and bound glycolytic enzymes from scorpionfish brain. II. Lactate dehydrogenase].

It is known that a part of lactate dehydrogenase in animal tissues is bound to the structural elements. However, if in the tissues of higher animals this part is insignificant, in fish tissues it can make tens of percent. The work is the continuation of a series of experiments on the comparative characteristic of the free and bound glycolytic enzymes in fish tissues, in this case-brain of the sea teleost scorpion fish. It was found that the sensitivity of LDH activity to different pH values and to the inhibition by high pyruvate concentrations were different for the both forms. The enzyme affinity for pyruvate and NADH was 4-6 times lower in free enzyme. Possible physiological significance of bound LDH form existence in the energy supply of the brain is discussed.