Reaction: phospholipid + 1,2-diacyl-sn-glycerol = lysophospholipid + triacylglycerol
ricinoleic acid = (9Z,12R)-12-hydroxyoctadec-9-enoic acid
vernolic acid = (9Z,12S,13R)-12,13-epoxyoctadec-9-enoic acid.
Other name(s): PDAT
Systematic name: phospholipid:1,2-diacyl-sn-glycerol O-acyltransferase
Comments: This enzyme differs from EC 126.96.36.199, diacylglycerol O-acyltransferase, by synthesising triacylglycerol using an acyl-CoA-independent mechanism. The specificity of the enzyme for the acyl group in the phospholipid varies with species, e.g., the enzyme from castor bean (Ricinus communis) preferentially incorporates vernoloyl (12,13-epoxyoctadec-9-enoyl) groups into triacylglycerol, whereas that from the hawk's beard (Crepis palaestina) incorporates both ricinoleoyl (12-hydroxyoctadec-9-enoyl) and vernoloyl groups. The enzyme from the yeast Saccharomyces cerevisiae specifically transfers acyl groups from the sn-2 position of the phospholipid to diacylglycerol, thus forming an sn-1-lysophospholipid.
Links to other databases: BRENDA, EXPASY, KEGG, Metacyc, CAS registry number: 288587-47-3
1. Dahlqvist, A., Stähl, U., Lenman, M., Banas, A., Lee, M., Sandager, L., Ronne, H. and Stymne, S. Phospholipid:diacylglycerol acyltransferase: An enzyme that catalyzes the acyl-CoA-independent formation of triacylglycerol in yeast and plants. Proc. Natl. Acad. Sci. USA 97 (2000) 6487-6492. [PMID: 10829075]