The acylation of lysophosphatidylcholine in the rat testicular tissue: the combined activity of acyl-CoA synthetase and lysolecithin acyltransferase.

The activity of lysophosphatidylcholine acyltransferase (EC 2.3.1.23) in combination with acyl-CoA synthetase (EC 6.2.1.3) has been determined in the homogenates and subcellular fractions of rat testis. The enzyme activity was found to be maximal at pH 7.4 ATP and CoASH were required for optimal incorporation of [1-14C] oleic acid into phosphatidylcholine. The sulfhydryl-binding reagents showed inhibitory effect on the acyltransferase activity. Dibutyryl cyclic AMP and beta-mercaptoethanol did not affect the enzyme activity. Subcellular distribution patterns of markers, marker enzymes and lysolecithin acyltransferase have shown that the acyltransferase activity was found to be predominantly localized in the microsomal fraction, though significant activity was also present in the mitochondrial fraction. These findings, together with our previous studies on testicular phospholipases A, suggest that the deacylation-reacylation cycle is operative in rat testicular tissue.