The Specific Acylation of Glycerol 3-Phosphate to Monoacylglycerol 3-Phosphate in Escherichia coli EVIDENCE FOR A SINGLE ENZYME CONFERRING THIS SPECIFICITY

Abstract Pronounced positional specificity during the acylation of glycerol 3-phosphate to form monoacylglycerol 3-phosphate has been shown with a particulate enzyme preparation from Escherichia coli. Palmitic acid is found to be esterified exclusively to position 1 while unsaturated fatty acids are predominantly esterified to position 2. Evidence for a single enzyme being involved in this specific acylation is presented. This evidence is based on studies of single site mutants of E. coli possessing a glycerol 3-phosphate acyltransferase of greatly increased thermolability and on chemical modification of the enzyme. Additional experiments show that the acylation of 1-acylglycerol-3-P involves an enzyme activity or activities separate from that which acylates glycerol-3-P.