Anabolic pathways for carbohydrate synthesisFig 20-1, Cox-LehningerPathways of gluconeogenesis and glycolysis.1.3 glycolytic reactions require bypass 2gy y qypmechanism for reversibility2.Energy balance of Gluconeogenesis 2 Pyruvate +2NADH + 6ATP 1 Glucose + 2NAD++ 6ADP + 6Pi3i3.Voet, Fundamentals, 3rdFig. 16.15Bypass reactions provide exergonic steps; all other stepsexergonic steps; all other steps are fully reversible since they operate close to chemical equilibriumqVoet, Fundamentals, 3rdFig. 16.21Conversion of pyruvate to oxaloacetate and then to phosphoenolpyruvate.in mitochondria in cytoplasmFig. 16.16Biotin and carboxybiotinyl–enzyme (a) Biotin consists of anprosthetic group of enzymesenzyme. (a) Biotin consists of an imidazoline ring that is cis-fused to a tetrahydrothiophene ring bearing a valerate side chain. b) enzymesIn carboxybiotinyl–enzyme, N1 of the biotin ureido group is the carboxylation site.Fig 16 17b(Biotin is a B-complex vitamin)Voet, Fundamentals, 3rdFig. 16.17bThe role of compartmentalization in controling metabolic pathways:Exporting mitochondrial reducing power (NADH/H+)Oxaloacetate Malate hondrion NADH/H+ NAD+MitochOxaloacetate MalatePEP + COOxaloacetate Malate NADH/H+ NAD+PEP + CO2Needed for GADPHGADPHMetabolic coupling of etabo c coup g osynthesis and energy availabilityAbiAbiAerobicAnaerobic(mitochondrial NADH not available)Ch20 Cox, Lehninger, 3rded,., 2001Phosphatases remove phosphates without regenerating ATPVoet, Fundamentals, 3rdFig. 16.15Eukaryotic G6Pase activity on endoplasmatic reticulum membrane; SP=G6Pase stabilizing Ca-binding
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