RBC Metabolism PDF

RBC Metabolism RBC membrane components Protein (52%) Lipid (40%) Carbohydrates (8%) A.Integral/transme A.External surface mbrane proteins B.Internal surface B.Peripheral / Cytoskeleton proteins 1. Embden Meyerhof Pathway (Glycolysis)...

RBC Metabolism RBC membrane components Protein (52%) Lipid (40%) Carbohydrates (8%) A.Integral/transme A.External surface mbrane proteins B.Internal surface B.Peripheral / Cytoskeleton proteins 1. Embden Meyerhof Pathway (Glycolysis) Glucose is metabolized in RBCs through anaerobic glycolysis (that requires no mitochondria and no oxygen). One molecule of glucose yields 2 molecules of ATP by one anaerobic glycolytic pathway. In addition, 2 molecules of lactate are produced. Lactate is transported to blood & in the liver it is converted to glucose. Genetic defects in enzymes of glycolysis: Genetic defects of one of the enzymes of glycolysis in RBCs results in a reduced rate of glycolysis in RBCs & by this way will deprive RBCs of the only means for producing energy. As a result, hemolytic anemia will be a consequence as RBCs will not be able to keep the biconcave flexible shape which allows it to squeeze through narrow capillaries with an end result of hemolysis (destruction of RBCs). 95% of cases of genetic defects in glycolytic enzymes is caused by pyruvate kinase deficiency. 4% is caused by phosphoglucose isomerase deficiency. Hexose Monophosphate Pathway Pentose Phosphate Shunt / Phosphogluconate Pathway Detoxifies accumulated peroxide Product : NADPH require: Glucose 6 Phosphate Dehydrogenase Oxidized glutathione Reduced Glutathione non functional functional Methemoglobin Reductase maintains the iron in Fe2+ state Cytochrome B5 reductase Rapaport-Leubering Pathway generates 2,3-bisphosphoglycerate (2,3-BPG) or 2,3 DPG Diphosphoglycerate