Glucose intermediate biochemical pathways

In this case, although the hypothetical balanced process yields a net 4 moles of methanol and 2 moles of CO2 per mole of glucose converted, twice the reducing power is needed compared to the ethanol case and cleavage of two additional carbon-carbon bonds is also required. Decarboxylation of pyruvic acid has not been reported to proceed in this manner. These observations, however, do not preclude the possibility of other biochemical pathways and intermediates to fermentation methanol. 

Fig. 11 Biochemical pathways for the formation, detoxification, and cellular effects of xenobiotic free radical intermediates and reactive oxygen species (ROS). Fe iron, G-6-P glucose-6-phos-phate, GSH glutathione, GSSG glutathione disulfide, H2O2 hydrogen peroxide, FIO hydroxyl radical, LPO lipoxygenase, NADP nicotinamide adenine dinucleotide phosphate, O2 superoxide, P450 cytochromes P450, PHS prostaglandin H synthase, SOD superoxide dismutase. (Modified from Wells et al. 1997)...

As well as being of biochemical interest glycolysis is commercially important it is used in the production of bread, beer, and wine. For a constant rate of glucose input, oscillation is observed in the rate of CO2 production as well as in the concentrations of many reaction intermediates.There are multiple feedback loops the control mechanism is far more elaborate than in any of the physicochemical oscillators discussed previously. We shall sketch some of the results to indicate the complexity of even a rather simple biochemical pathway. 

The rearrangement is of interest because the corresponding enzymatic interconversion of aldoses and ketoses is an important part of the biosynthetic, photosynthetic, and metabolic pathways, as we shall see in Section 20-9. Although the biochemical rearrangement also may proceed by way of enediol intermediates, it is highly stereospecific and yields only one of two possible stereoisomeric aldoses. For example, glucose, but not mannose, can be enzymatically interconverted with fructose as the 6-phosphate ester derivative ... 

Two phosphate esters, fructose 6-phosphate and fructose 1,6-diphosphate (the Harden-Young ester) are biochemically significant because they are intermediates in the breakdown of glucose according to the Embden-Meyerhof pathway (Section 7) this pathway is actually the route of breakdown of fructose 1,6-diphosphate. 

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