120 likes | 283 Views
Catabolism s of triacylglycerols and phospholipids. Synthesis of Triacylglycerols (TGs) and Glycerophospholipids (GPLs). Glycerol 3-phosphate can be obtained either by the reduction of dihydroxyecetone phosphate (primarily) or by the phosphorylation of glycerol (to a lesser extent).
E N D
Synthesis of Triacylglycerols (TGs) and Glycerophospholipids (GPLs) Glycerol 3-phosphate can be obtained either by the reduction ofdihydroxyecetone phosphate (primarily) or by the phosphorylation of glycerol (to a lesser extent).
Formation of phosphatidate Two separate acyl transferases (AT) catalyze the acylation of glycerol 3-phosphate. The first AT (esterification at C1) has preference for saturated fatty acids; the second AT (esterification at C2) prefers unsaturated fatty acids.
Phosphatidic acid(phosphatidate)is an common intermediate in the synthesis of TGs and GPLs Phosphatidate can be converted to two precursors: - diacylglycerol (precursor for TGs and neutral phospholipids) - cytidine diphosphodiacylglycerol(CDP-diacylglycerol) (precursor for acidic phospholipids)
Synthesis of TGs and neutral phospholipids Phospha- tidyl- etha-nolamine Triacyl-glycerol Phosphatidylcholine
Synthesis of TGs Diacylglycerol can be acylated to triacylglycerol (in adipose tissue and liver) Enzyme: acyltransferase
Synthesis of neutral phospholipids CDP-choline or CDP-ethanolamine are formed from CTP by the reaction: CTP + choline phosphate CDP-choline + PPi CTP + ethanolamine phosphate CDP-ethanolamine + PPi Diacylglycerol react with CDP-choline or CDP-ethanolamine to form phosphatidylcholine or phosphatidylethanolamine
Phosphatidylinositol can be converted to phosphatidylinositol 4,5-biphosphate which is the precursor of the second messenger inositol 1,4,5-triphosphate
Interconver-sions of phosphati-dylethanol-amine and phospha-tidylserine