The Oxidation of Sodium Lactate by Hydrogen

The consideration of the manner in which various metabolites are removed from the living cell by the process of oxidation presents a problem which, if it is to be considered quantitatively, necessitates a detailed knowledge of the course of comparable reactions in vitro. I t is, therefore, desirable to consider such reactions from many points of view before attempting to analyze the more complicated reactions that are associated with the living tissue. Starting with the admirable researches of Fletcher (1) increasing importance has been attached to variations in the concentration of lactic acid in the animal body. There is, however, very little known about the manner in which lactic acid disappears after its production during muscular contraction. The conditions regarding this phase of muscle physiology have recently been reviewed by Shaffer (2), who points out that there are four ways in which lactic acid may disappear in the animal body. There is the possibility that there may be a coupled reaction, part of the lactic acid being oxidized to provide energy to reconvert the remainder to glucose. Again, there may be a conversion of all the lactic acid to glucose, the oxidation of some other metabolite producing this energy. The third possibility is that part of each molecule of the lactic acid is oxidized with a production of acetaldehyde, which in turn is converted into glucose. Finally, there is the possibility that the lactic acid is entirely burned. In view of these manifold possibilities a knowledge of the changes in vitro is desirable. Such reactions were first studied, in the case of lactic acid, by Fenton (3) who found that there was a slow oxidation of lactic acid by H202. Later the problem was taken up by Dakin (4) who investigated it in much greater detail. In both researches attention was directed toward the various products of the reaction rather than to the manner in which the reaction took place. 509