Modulation of acylglycerol synthetase activities of rat intestinal mucosa by homogenization and sonication.

Diacylglycerol and triacylglycerol synthesis was compared in intact villus cells and in their homogenates and sonicates using 2-monoacylglycerols and free fatty acids as substrates along with appropriate cofactors. It was found that simple pestle homogenization of cells led to an apparent loss of 80-90% in the triacylglycerol and 40-fold increase in the diacylglycerol synthetase activity. Sonication of the homogenate resulted in reestablishing the normal activity of cellular triacylglycerol synthesis (12 +/- 1 nmol . mg protein-1 . h-1) but the diacylglycerol biosynthesis further increased (to a maximum of 70 +/- 5 nmol . mg protein-1 . h-1). Preincubation with trypsin and postincubation treatment with pancreatic lipase indicated that different enzymes are involved in diacylglycerol and triacylglycerol biosynthesis from 2-monoacylglycerols and that these enzymes become segregated during homogenization. It is concluded that a triacylglycerol synthetase system utilizing 2-monoacylglycerols can be reassembled upon sonication.