Pathways of Sugar Metabolism: Pentose Phosphate Pathway, Fructose, and Galactose Metabolism
ثبت نشده
چکیده
Enzymes can generally use either NADPH or NADH, but not both. Reactions requiring the input of electrons as hydride ions are usually catalyzed by enzymes specific for NADPH. Fig. 29.1. Fructose. The sugar fructose is found in the diet as the free sugar in foods such as honey or as a component of the disaccharide sucrose in fruits and sweets. It also can be synthesized from glucose via the polyol pathway. In the lens of the eye, the polyol pathway contributes to the formation of cataracts. Fructose is metabolized by conversion to intermediates of glycolysis. 29 Pathways of Sugar Metabolism: Pentose Phosphate Pathway, Fructose, and Galactose Metabolism
منابع مشابه
Evidence that glutamine, not sugar, is the major energy source for cultured HeLa cells.
Cultured HeLa cells grew at a similar rate when the sugar source was either glucose, galactose, or fructose. The relative rates of carbon flow through glycolysis and the pentose phosphate cycle, as well as total utilization, were a function both of the sugar and its concentration. When 21 mu, about 80% of the glucose carbon was metabolized through glycolysis to lactic acid, but only 4 to 5% of ...
متن کاملCarbohydrate Metabolism
G lucose is central to all of metabolism. It is the universal fuel for human cells and the source of carbon for the synthesis of most other compounds. Every human cell type uses glucose to obtain energy. The release of insulin and glucagon by the pancreas aids in the body’s use and storage of glucose. Other dietary sugars (mainly fructose and galactose) are converted to glucose or to intermedia...
متن کاملLiver glucose metabolism in humans
Information about normal hepatic glucose metabolism may help to understand pathogenic mechanisms underlying obesity and diabetes mellitus. In addition, liver glucose metabolism is involved in glycosylation reactions and connected with fatty acid metabolism. The liver receives dietary carbohydrates directly from the intestine via the portal vein. Glucokinase phosphorylates glucose to glucose 6-p...
متن کاملCarbohydrate Degradation Pathways in Thiobacillus A2 Grown on Various Sugars
A detailed radiorespirometric and enzymological analysis was made of the wild-type and GFI strains of Thiobacillus A2 grown on numerous sugars. The wild-type used the EmbdenMeyerhof, Entner-Doudoroff and pentose phosphate pathways for glucose oxidation only after culture on glucose. The fast-growing strain GFI used all three pathways after growth on glucose, maltose or fructose. The wild-type g...
متن کامل31P and 13C nuclear magnetic resonance studies of metabolic pathways in Pasteurella multocida characterization of a new mannitol-producing metabolic pathway.
Glucose metabolism of Pasteurella multocida was examined in resting cells in vivo using 13C NMR spectroscopy, in cell-free extracts in vitro using 31P NMR spectroscopy and using enzyme assays. The NMR data indicate that glucose is converted by the Embden-Meyerhof and pentose phosphate pathways. The P. multocida fructose 6-phosphate phosphotransferase activity (the key enzyme of the Embden-Meyer...
متن کامل