Glucose formation

The reverse of this reaction does occur in some cells (e.g. hepatocytes), catalysed by the enzyme glucose-6-phosphatase, but the direction is always towards glucose formation, i.e. glucose 6-phosphate is never produced by this reaction in vivo. The question is, why not ... 

Gluconeogenesis glucose formation from non-carbohydrate sources... 

GLUCONEOGENESIS GLUCOSE FORMATION FROM NON-CARBOHYDRATE SOURCES... 

In lean subjects, amino acid oxidation, via glucose formation and glucose oxidation, provides almost four times more energy than in the obese snbjects (Table 16.4). That is, the obese lose protein mnch more slowly, which may be an important factor favouring survival of the obese in starvation. This is consistent with the fact that, from the data available, obese subjects have survived starvation approximately fonr times longer than the lean (abont 300 days versns 60-70 days Table 16.5). 

Specific determination of D-glucose (65) in plant exfi acts requires high purity GOX, devoid of /6-glucosidase, to avoid interference by hydrolysis of oligo- and polysaccharides that may lead to glucose formation and produce H2O2 on autoxidation ". ... 

Carbohydrate action of glucocorticoids is defined as the stimulation of glucose formation, diminution of its use, and promotion of its storage as glycogen. 

Notice that this enzyme is named for the reverse reaction in the cell, the reaction proceeds in the direction of UDP-glucose formation, because pyrophosphate is rapidly hydrolyzed by inorganic pyrophosphatase (Fig. 15-7). 

Starch synthesis is regulated at the level of ADP-glucose formation, as discussed below. 

Wemer, I., Bacher, A., and Eisenreich, W., 1997, Rctrobiosynthctic NMR studies with 13C-labeled glucose. Formation of gallic acid in plants and fungi, J. Biol. Chem. 272 25474-25482. 

The formation of D-glucose in the later stages of the reaction, that is, in the saccharification, shows that at least one terminal linkage can be attacked, but the velocity of the D-glucose formation is very low compared to the velocity of the dextrinization.)... 

Radioisotopes can also be used to follow the course of an element through a chemical reaction. For example, CO2 gas containing radioactive carbon-14 isotopes has been used to study glucose formation in photosynthesis. 

The sources of carbon for hepatic glucose formation are hepatic glycogen, lactate from red blood cells or skeletal... 

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