Formation of acetyl from succinate by rabbit liver slices.

In the course of a study of the mammalian metabolism of succinate, liver slices derived from rabbits previously given intraperitoneal injections of sodium pantothenate were incubated with succinic acid-l ,4-Cl4 and sulfanilamide (1). Acetylsulfanilamide isolated from the reaction mixture proved to be radioactive, and degradation revealed that all of the Cl* in this product resided in the carboxyl carbon of the acetyl moiety. Known and proposed biochemical transformations suggest several mechanisms to account for the conversion of succinate into “acetyl.” The present report deals with experiments designed to evaluate these several possibilities and to indicate the mechanism which may account for the initial observation. Experiments with deuterium-labeled and Cl*-labeled succinic acid and with radioactive bicarbonate have permitted the exclusion of certain postulated mechanisms and have indicated the occurrence of others.