Mechanism of diacylglycerophosphate synthesis in Mycobacteria.

Phospholipids from Mycobacteria have an unusual fatty acid pattern; palmitic acid is mainly on position 2 while oleic acid is found predominantly at position 1 of glycerophospholipids (Okuyama, H., Kankura, T., and Nojima, S. (1967) J. Biochem. (Tokyo) 61, 732-737). Membrane preparations were obtained from Mycobacterium butyricum, which had acyl-CoA:glycerophosphate and acyl-CoA:monoacylglycerophosphate acyltransferase activities. Diacylglycerophosphate was synthesized from glycerophosphate through both I-acylglycerophosphate and 2acylglycerophosphate as intermediates. The glycerophosphate acyltransferase system to form l-acylglycerophosphate incorporated palmitate and oleate at a comparable rate while the system to form 2-acylglycerophosphate was relatively more specific for palmitate. The 2-acylglycerophosphate acyltransferase system was highly specific for oleate while the I-acylglycerophosphate acyltransferase system incorporated palmitate and oleate at a comparable rate, although the activity of the latter system was much lower. In the presence of palmitoyl-CoA and oleoyl-CoA, loleoyl-2-palmitoyl-glycerophosphate was mainly synthesized from glycerophosphate. Thus, the mycobacterial phospholipids with an unusual fatty acid pattern appear to be synthesized mainly through the 2-acylglycerophosphate pathway.