The possible selectivity of the acyl-CoA:1,2-diacyl-sn-glycerol acyltransferase in rat liver microsomes towards different molecular species of 1,2-diacyl-sn-glycerols was studied. Triacylglycerol synthesis was determined by monitoring the entry of radioactive palmitate from [1-14C]palmitoyl-CoA into triacylglycerol in the presence of various diacylglycerols. The diacylglycerol acyltransferase did not exhibit any selectivity against hexaenoic precursors under the assay conditions used (0.25 mM diacylglycerol in medium) and the rates of triacylglycerol synthesis observed with the various diacylglycerols were not significantly different when the data were analyzed statistically. The results suggest that the extremely low level of docosahexaenoic acid in triacylglycerols cannot be attributed to a discrimination of the diacylglycerol acyltransferase against 1-saturated 2-docosahexaenoyl precursors.
Expression of a type 2 diacylglycerol acyltransferase fromThalassiosira pseudonanain yeast leads to incorporation of docosahexaenoic acid β-oxidation intermediates into triacylglycerol