Incorporation of L-α-glycerophosphate and acyl-S-CoA into lipids by microsomes of Galleria mellonella

Abstract

Microsomal preparations from the wax moth, Galleria mellonella, rapidly incorporated L-α-glycerophosphate and the acyl components of palmitoyl and stearoyl coenzyme A into glycerides. The rate of incorporation increased with pH at least up to pH 9.0 but so did enzyme inactivation; therefore a pH of 7.5 at 30 °C was adopted for the study.The incorporation of glycerophosphate did not proceed in the absence of added acyl-S-coenzyme A, but the amount of acylation required for the observed incorporation of glycerophosphate was of a greater order of magnitude than the amount of acyl-S-CoA added to the reaction mixture. It appears that the added acyl-S-CoA was acting as a positive effector for the release of endogenous acyl groups which also served as substrate for acylation.There was also evidence of an amount of endogenous acyl acceptor.The intervention of various amounts of endogenous substrates must confuse attempts to determine transacylase specificity by measuring relative rates of incorporation of exogenous substrates in microsomal preparations from the wax moth.