STUDIES ON THE METABOLISM OF 1,2-PROPANEDIOL-1-PHOSPHATE

Abstract

Hanzlik et al. (1) observed the glycogenic action of propylene glycol in rats, and Lindberg (2) has isolated its phosphorylated ester from sea urchin eggs. The latter worker has subsequently demonstrat’ed the presence of 1 ,%propanediol phosphate (PDP) in other t’issues (3). Rudney (4, 5) has suggested that PDP might be an intermediate in the conversion of acetone to “formate” and Cz fragment, while Sakami and Lafaye (6) have suggested that PDP is an intermediate in Ohe metabolism of acetone and a precursor of a 3-carbon compound of the glycolytic cycle. Reports from this laboratory have suggested an alternative pathway of 3-carbon compounds of the glycolytic cycle (7, 8). It appeared to us that PDP might be an intermediate in the alternative pathway suggested by experiments in which slices of heart ventricle anabolizing lactic acid were not inhibited by a concentrat’ion of fluoride sufficient to inhibit enolase. Further, it occurred to us, in view of the recent observations of Harting (9), t,hat PDP might react in the same enzyme systems that normally oxidize cY-glycerophosphate, provided the primary alcohol group is not essential for cr-glycerophosphate dehydrogenase activity. The work reported here demonstrates the oxidation of PDP by a-glycerophosphate dehydrogenase and the removal of the end-product of this oxidation by a further oxidation by addition of a heart muscle extract (10). It has been found that a crystalline preparation of n-glyceraldehyde-3phosphate dehydrogenase will replace the heart’ muscle extract. The data suggest a new series of reactions by which the carbon of PDP might be diverted into pyruvic acid of the glycolytic cycle.