Nicotinamide, Cozymase and Tissue Metabolism

Abstract

THE importance of cozymase as a fundamental constituent of certain respiratory processes in the living cell is now well established. It is known that cozymase is necessary for the activity in animal tissues of specific dehydrogenases oxidizing alcohol, lactate, malate, triosephosphate, etc. Its mode of action is reasonably clear. After combination with a dehydrogenase, it is reduced by a substrate (for example, lactate) with the formation of reduced cozymase and the oxidized product of the substrate (for example, pyruvate). The reduced cozymase is oxidized to its original form by other enzyme systems in the cell, transfer of hydrogen from the substrate to the final oxidizing agent being thus accomplished. Cozymase acts as a catalyst in the transfer of hydrogen in the cell, and in the intact tissue a dynamic equilibrium between reduced and oxidized cozymase is presumably always maintained.