In 1948, Ogston (1) postulated the existence of an asymmetric enzyme able to distinguish between one of two identical groups in a symmetrical compound. Shortly thereafter, Potter and Heidelberger (2) accomplished the biosynthesis of an “asymmetrically” labeled citric acid, substantiating Ogston’s principle. That glycerol, another compound of chemical symmetry, might also be biologically asymmet...

The effect of methotrexate on lipids in serum and liver and key enzymes involved in esterification and oxidation of long-chain fatty acids were investigated in rats fed a standard diet and a defined choline-deficient diet. Hepatic metabolism of long-chain fatty acids were also studied in rats fed the defined diet with or without choline. When methotrexate was administered to the rats fed the st...