2-Methylbutyryl-CoA: succinate acyl-CoA transferase activity and function in Ascaris suum muscle.

A branched-chain acyl-CoA transferase activity which transfers coenzyme A from either 2-methylbutyryl or 2-methylvaleryl-CoA to succinate is present in the muscle mitochondria from the intestinal nematode, Ascaris suum. Its physiological function is discussed. This activity appears to differ from the previously described acetyl-CoA: propionate and propionyl-CoA:succinate acyl-CoA transferases on the basis of heat stability, substrate specificity and the requirement of a "factor" from boiled Ascaris mitochondria for optimal activity of only the branched-chain acyl-CoA transferase. The "factor" has been recovered from HPLC and some of its properties examined. It could not be replaced by a crude soluble fraction from rat liver mitochondria, or by adenine, guanine or inosine di- or triphosphates. Activity was lost upon ashing, but was not affected by treatment with either pepsin or chymotrypsin.