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O. O. O. R-C-O. O-C-R. O-C-R. Triacylglycerol Synthesis. Fatty acyl-CoA DHAP reduction to glycerol-PO 4 or Glycerol kinase to glycerol-PO 4 Two esterifications Diacylglycerol-PO 4 intermediate Triacylglycerol. glycolysis. NADH + NAD +. ADP ATP. CH 2 OH. C=O. CH 2 OP.
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O O O R-C-O O-C-R O-C-R Triacylglycerol Synthesis • Fatty acyl-CoA • DHAP reduction to glycerol-PO4 or • Glycerol kinase to glycerol-PO4 • Two esterifications • Diacylglycerol-PO4 intermediate • Triacylglycerol
glycolysis NADH + NAD+ ADP ATP CH2OH C=O CH2OP CH2OH CH2OH O O Not in adipose tissue O O O 2 HO-C-H HO-C-H R-C~CoA R-C~CoA CH2O-C-R CH2O-C-R CH2O-C-R O O O CH2OH CH2OP R-C-O-C-H R-C-O-C-H R-C-O-C-H CH2OH CH2OP CH2O-C-R H2O PO4 O Triacylglycerol Biosynthesis glycerol kinase glycerol-PO4 dehydrogenase DHAP Glycerol-PO4 Phosphatidic acid Phospholipid biosynthesis 1,2 Diacylglycerol (DAG)
Question • Can a triacylglycerol (triglyceride) storage fat be synthesized entirely from glucose, i.e., every carbon in the fat comes from a sugar? • Answer: YES
Phosphatidic Acid O - or + - or + O O O Ester linkage O O CH2O-C-R CH2O-C-R O O R-C-O-C-H R-C-O-C-H CH2OPO-CH2CH2-N(CH3)3 CH2OP O O Phospholipid Biosynthesis (smooth ER) Polar component = choline, serine, ethanolamine, etc Glycerophospholipids + Phosphatidylcholine or lecithin
PPP- Ribose CTP Strategy of Glycerophospholipid Biosynthesis • Activate diacylglycerol • Activate appending moiety (salvage)
O CH2O-C-R O R-C-O-C-H CH2OP~P-ribose-Cytosine (CDP-diacylglycerol) Bacteria (Prokaryotes) Activate Phosphatidic acid CDP-diacylglycerol + PPi Phosphatidic acid + CTP
Serine Glycerol-PO4 CMP CMP Phosphatidyl- glycerol CO2 glycerol Wassermann antigen for diagnosing syphilis Most prominent membrane lipid in bacteria Bacteria (Prokaryotes) CDP-diacylglycerol Phosphatidylserine Phosphatidylglycerol-3-PO4 Phosphatidylethanolamine Cardiolipin
1 2 3 O O CH2O-C-R CH2O-C-R O O R-C-O-C-H R-C-O-C-H CH2OP CH2OH Pi Eukaryotes ATP Glycerol Glycerol-3-PO4 DHAP FA-CoA 1-Acyl-DHAP Phosphatidic acid NADPH DAG 1-Acyl-glycerol-3-PO4 ATP CTP CDP-diacylglycerol ethanolamine (CDP-ethanolamine) choline (CDP-choline) Serine (phosphatidylethanolamine) Glycerol (CDP-diacylglycerol) Inositol (CDP-diacylglycerol) 1,2 DAG Cardiolipin (phosphatidylglycerol)
N H 2 N O O O N + H O P N C H C H O P O C H 2 2 2 3 O O O H O ethanolamine O H C y t i d i n e d i p h o s p h a t e ( C D P )
ATP ADP O HO-P- O-CH2-CH2-NH3+ O- CTP PPi O O Cytidine- -P- O-P- O-CH2-CH2-NH3+ O- O- DAG CMP Serine Ethanolamine SALVAGE Ethanolamine or choline HO-CH2-CH2-NH3+ Ethanolamine kinase or choline kinase Phosphoethanolamine CDP-ethanolamine Phosphatidylethanolamine Phosphatidylserine