Dual Localization of Long‐Chain Acyl‐CoA Hydrolase in Rat Liver: One in the Microsomes and One in the Mitochondrial Matrix

Open Access
Publisher Website
Google Scholar
Abstract
Subcellular fractionation studies of rat liver localized the activity of palmitoyl-l-carnitine hydroalse to the microsomal fraction whereas palmitoyl-CoA hydrolase activity was found both in the microsomal fraction and in mitochondria. An unusual biphasic saturation curve for palmitoyl-CoA was observed when intact mitochondria were used, possibly reflecting the existence of an intramitochondrial hydrolase activity. Disruption of the mitochondrial structure doubled the palmitoyl-CoA hydrolysis. Discontinuous sucrose gradient centrifugation and digitonin of rat liver mitochondria demonstrated that a palmitoyl-CoA hydrolase was associated with the matrix fraction. Pure matrix and microsomal fractions showed that the two hydrolase activities were differently affected by the presence of divalent cations. Both the specific activity and the saturation concentration of palmitoyl-CoA were higher for the microsomal enzyme than for the matrix-associated enzyme.