Glycerate-l,3-bisphosphate

Except for glycerate-l,3-bisphosphate all of the intermediates in the pathway are pictured as belonging to one of three metabolic pools. Within each metabolic pool the intermediates are readily interconvertible and usually present in relative concentrations close to their equilibrium values. Between the pools the concentrations of the intermediates can be very different because of the lack of rapid intercon-... 

Regeneration of NAD+ by reduction of pyruvate to lactate. Because NAD+ is a necessary participant in the oxidation of glyceraldehyde-3-phosphate to glycerate-l,3-bisphosphate, glycolysis is possible only if there is a way by which NADH can be reoxidized. 

Other enzymes in the stroma can convert glycerate-3-phosphate back to ribulose-1,5-bisphosphate. The reactions of this reductive pentose cycle, or Calvin cycle, are shown in figure 15.25. 3-Phosphoglycerate is first phosphorylated to glycerate-l,3-bisphosphate at the expense of ATP and then reduced to glyceraldehyde-3-phosphate by NADPH. (Note that the nucleotide specificity in the reductive step differs from that of the cytosolic glyceraldehyde-3-phos-... 

Phosphoryl group transfer. In this reaction ATP is synthesized as phos-phoglycerate kinase catalyzes the transfer of the high-energy phosphoryl group of glycerate-l,3-bisphosphate to ADP ... 

Reaction 7 is an example of a substrate-level phosphorylation. Because the synthesis of ATP is endergonic, it requires an energy source. In substrate-level phosphorylations, ATP is produced because of the transfer of a phosphoryl group from a substrate with a high phosphoryl group transfer potential. Because two molecules of glycerate-l,3-bisphosphate are formed for every glucose molecule, this reaction... 

The hydrolysis of glycerate-l,3-bisphosphate generates 1 mol of ATP. Recall that aerobic respiration is stimulated by relatively high ADP concentrations and inhibited by relatively high ATP concentrations. Any measurable increase in ATP concentration has the effect of depressing aerobic respiration. Also recall that ATP is an inhibitor of PFK-1 and pyruvate kinase, enzymes required to channel carbon skeletons into the citric acid cycle. 

Carbon 2 in glycerate-2,3-bisphosphate is in the D configuration. Would you expect the l configuration of glycerate-2,3-bisphosphate to have the same effect on the biochemistry of hemoglobin Why or why not ... 

D-Fructose-l,6-bisphosphate d- glycer aldehyde-3 -phosphate-lyase O .. Aldolase ALD... 

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