魚類組織の酸化型および還元型NADおよびNADPの含量について

抄録

Methemoglobin reductase and metmyoglobin reductase, which have been studied as a part of research for the maintenance of fish meat color, were found to catalyze the reduction of methemoglobin and metmyoglobin by NADPH (or NADH) in the presence of methylene blue. The distribution of these coenzymes in living organisms has been examined mostly for plant or mammals, and only few studies have been done for fishes. The present report describes the concentration of NAD, NADH, NADP and NADPH in the fish tissues.
The concentration of these coenzymes and oxidoreduction rate in the muscle and other tissues of fishes were determined by the enzymic methods. The total amount of NAD and NADH in the ordinary muscle was about 20 mg% throughout all the fishes examined, being several times as much as the total amount of NADP and NADPH in the same muscle. The total amount of each coenzyme in the red muscle was more than twice its quantity in the ordinary muscle. The total amounts in the internal organs or blood were several times as much that in the ordinary muscle, The ratio between NAD (H) and NADP (H) in these tissues did not differ from that in the ordinary muscle. Each coenzyme was found to exist only in a reduced form in almost all the cases. This fact is different distinctly from the observation of mammals, and it may be a specific character for fishes.