Partial Purification and Properties of an Acyl Coenzyme A:sn-Glycerol 3-Phosphate Acyltransferase from Rat Liver Mitochondria

Abstract

The partial purification (6-fold) and properties of a position and substrate specific acyl coenzyme A:sn-glycerol-3-P acyltransferase from rat liver mitochondria are described. The preparation is devoid of acyl-CoA:monoacylglycerol-3-P acyltransferase and lipid phosphomonoesterase activity. All of the glycerol-3-P acylated in the presence of palmityl-CoA is identified as 1-palmityl-sn-glycerol-3-P. The order of effectiveness of various acyl-CoA donors is palmityl > stearyl ≃ myristyl > decanyl-CoA. Oleyl- and linoleyl-CoA were about 5% as effective as palmityl-CoA. Palmitic acid was esterified exclusively in position 1 of the sn-glycerol molecule. The activity is stimulated by phosphatidyl serine, asolectin, and lecithin, whereas cardiolipin, lysophosphatidic acid, and phosphatidic acid were inhibitory. Mg++, Ca++, Mn++, and to a lesser extent Co++ enhance the activity. The findings demonstrate that the acylation of sn-glycerol-3-P involves an enzyme activity separate from that which acylates 1-palmityl-sn-glycerol-3-P. The enzyme preparation offers a convenient and efficient method for the preparation of 1-palmityl-sn-glycerol 3-phosphate.