Phosphatidic acid metabolism in rat liver microsomes.
Rat liver microsomes contain phosphatidate phosphatases which split phosphatidic acid into inorganic phosphate and diacylglycerol and a system of phospholipases and lipases, which split phosphatidic acid into free fatty acids, glycerol and inorganic phosphate. In the presence of ATP,CoA and [1-14C]palmitate, part of the monoacyl-sn-glycerol 3-phosphate formed by phospholipase action is reesterified, yielding radioactive phosphatidic acid. The sum of di- and triacylglycerols formed from phosphatidic acid in the presence of ATP and CoA exceeded the amount of diacylglycerol formed in their absence. The yield of neutral lipids from sn-glycerol 3-phosphate and monoacyl-sn-glycerol 3-phosphate markedly exceeded that from phosphatidic acid. Comparison of the yields of di- and triacylglcerols from glycerol-labelled and fatty-acid-labelled phosphatidic acid was used to establish the extent of deacylation and reacylation. About 60% of the diacylglycerol was formed by direct dephosphorylation. The triacylglycerols, on the other hand, were formed almost exclusively from recycled phosphatidic acid.
D000255:Adenosine Triphosphate / Q000494:pharmacology; D000818:Animals; D003065:Coenzyme A / Q000494:pharmacology; D004075:Diglycerides / Q000096:biosynthesis; D008862:Microsomes, Liver / Q000378:metabolism*; D010169:Palmitic Acids / Q000378:metabolism; D010712:Phosphatidic Acids / Q000096:biosynthesis / Q000378:metabolism*; D010743:Phospholipids / Q000378:metabolism*; D010744:Phosphoric Monoester Hydrolases / Q000378:metabolism; D051381:Rats; D014280:Triglycerides / Q000096:biosynthesis
D004075:Diglycerides; D010169:Palmitic Acids; D010712:Phosphatidic Acids; D010743:Phospholipids; D014280:Triglycerides; D000255:Adenosine Triphosphate; D010744:Phosphoric Monoester Hydrolases; D003065:Coenzyme A