The central importanceof cytidine nucleotides in lipid biosynthesis was discoveredby Eugene P. Kennedy in the early 1960s.
Synthesis of phosphatidylcholine, phosphatidylethanolamine, and phosphatidylserine. The multiple pathways reflect the importanceof phospholipids in membrane structure. For example, phosphatidylcholine (PC) can be synthesized from dietary choline when it is available. Ifcholine is not available, PC can be made from dietary carbohydrate, although the amount synthesized is inadequate to prevent choline deficiency.SAM is S-adenosylmethionine, a methyl group donor for many biochemical reactions (see Chapter 40).
B. Degradation of GlycerophospholipidsPhospholipases located in cell membranes or in lysosomes degrade glycerophospholipids.Phospholipase A1 removes the fatty acyl group on carbon 1 of the glycerolmoiety, and phospholipase A2 removes the fatty acid on carbon 2 (Fig. 33.31). TheC2 fatty acid in cell membrane phospholipids is usually an unsaturated fatty acid,which is frequently arachidonic acid. It is removed in response to signals for the synthesisof eicosanoids. The bond joining carbon 3 of the glycerol moiety to phosphateis cleaved by phospholipase C. Hormonal stimuli activate phospholipase C, whichhydrolyzes PIP2 to produce the second messengers DAG and inositol triphosphate(IP3). The bond between the phosphate and the head group is cleaved by phospholipaseD, producing phosphatidic acid and the free alcohol of the head group.
Globosides are glycolipids containing multiple sugar unitsKidney and RBCDeterminant of blood group
Lipid metabolism metabolism of complex lipids ppt BIOCHEMISTRY firstname.lastname@example.org
Dr. Vijay Marakala, MBBS, MD.
SIMS & RC