AbstractsBiology & Animal Science

The Tricarboxylic Acid Cycle is now believed to represent the main pathway for the oxidative metabolism of carbohydrate, fat and protein. The compounds of the Cycle are dicarboxylic and tricarboxylic acids that arise in the course of the metabolism of these substances. The development of the Cycle began with the systematic search by Thunberg (1) (1906-1920) for substances that could be metabolized by animal tissues. Using the acceleration of the decolorization of methylene blue by the tissue as the criterion that an added substrate was oxidized, Thunberg listed lactate, succinate, fumarate, malater citrate and glutamate, among many other substances, as metabolites. This work was confirmed and extended by Batelli and Stern (2). Enzymatic studies of the oxidation of the dicarboxylic acids revealed their close relationship in metabolism; the series of reactions. Succinate⇌Fumarate⇌Malate⇌Oxalacetate was established (3, page 203).[...]