3-P-glycerate-kinase

Anderson, L.E. and Carol, A.A. (2005) Enzyme co-localization in the pea leaf cytosol 3-P-glycerate kinase, glyceraldehyde-3-P dehydrogenase, triose-P isomerase and aldolase. Plant Sci 169, 620-628... 

Fig. 11. 3 P-NMR spectra of equilibrium mixtures of (A) rabbit muscle pyruvate kinase (Nageswara Rao et al 1979) and (B) yeast 3-P-glycerate kinase (Nageswara Rao et al 1978b) at catalytic and stoichiometric enzyme concentrations. Spectra for pyruvate kinase were obtained at 40.3 MHz, 15 C, and pH 8.0 for 3-P-glycerate kinase catalytic equilibrium mixture was recorded at 24 MHz and stoichiometric equilibrium mixtures at 109.3 MHz, 1°C, and pH 7.0. The appearance a small P-enolpyruvate signal in the catalytic equilibrium mixture of pyruvate kinase occurs in the presence of a 15-fold excess of pyruvate over ATP. Shifts upheld are negative.

P-glycerate kinase reaction. Fig. 11 also shows the effect of sulfate ion on the spectrum of the stoichiometric equilibrium mixture. That is nearly equal to 1 for arginine kinase, creatine kinase and adenylate kinase for which indicates significant catalysis in either direction, or for 3-P-glycer-... 

Glucose-6-P is then isomerized by phosphohexose isomerase to fructose-6-P (making up 30% of the equilibrium mixture). Another kinase phosphorylates the 1-position and the resulting fructose diphosphate is cleaved in an equilibrium reaction to two trioses, namely dihydroxyacetone phosphate (C-1 to C-3) and glyceral-dehyde phosphate (C-4 to C-6). The equilibrium mixture is composed of 89% hexose and 11% triose (under the conditions of Meyerhof s measurements) condensation, therefore, is the preferred (= exergonic) reaction. The reaction is analogous to the aldol condensation described in organic chemistry (Chapt. 1-2, XV-5). Catalysis of the reverse reaction by the enzyme aldolase is explained by the fact that enzymes always catalyze up to the equilibrium. ... 

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