Figure 2.

OGDHC activity as a function of different substrate and product concentrations. (A) OGDHC activity as a function of 2-oxoglutarate concentration at different NAD and CoASH concentrations in the absence of products. Kinetic data were obtained from Figure One A of [20]. Concentration of substrates NAD and CoASH in the assay were fixed to: 0.033 mM and 0.005 mM (square); 0.066 mM and 0.01 mM (down-triangle); 0.133 mM and 0.02 mM (up-triangle); 0.333 mM and 0.05 mM (circle). (B) OGDHC activity as a function of CoASH concentration at different 2-oxoglutarate and NAD concentrations in the absence of products. Kinetic data were obtained from Figure One B of [20]. Concentration of the substrates 2-oxoglutarate and NAD in the assay were fixed to: 0.025 mM and 0.02 mM (square); 0.05 mM and 0.04 mM (down-triangle); 0.1 mM and 0.08 mM (up-triangle); and 0.5 mM and 0.4 mM (circle). (C) OGDHC activity as a function of NAD at different 2-oxoglutarate and CoA concentrations in the absence of products. Kinetic data were obtained from Figure One C of [20]. Concentration of the substrates 2-oxoglutarate and CoASH in the assay were fixed to: 0.05 mM and 0.005 mM (square); 0.1 mM and 0.01 mM (down-triangle); 0.2 mM and 0.02 mM (up-triangle); and 0.5 mM and 0.05 mM (circle). (D) OGDHC activity as a function of NAD at different 2-oxoglutarate and CoASH concentrations in the presence of products NAGH. Kinetic data were obtained from Figure Two B of [20] and rescaled for data consistence. Concentration of the substrates 2-oxoglutarate and CoASH in the assay were fixed to: 0.5 mM and 0.05 mM. NADH concentration were 0.0 (circle), 0.01 mM (up-triangle), 0.02 mM (down-triangle) and 0.05 mM (square). (E) OGDHC activity as a function of CoASH concentration in the presence of product Succinyl-CoA. Kinetic data were obtained from Figure Five A of [10]. Concentration of the substrates 2-oxoglutarate and NAD in the assay were fixed to: 1.0 mM and 336 μM. Succinyl-CoA concentration were 0.0 (circle), 6.6 μM (up-triangle), and 13.2 μM (down-triangle). (F) OGDHC activity as a function of CoASH concentration in the presence of products Succinyl-CoA and NADH. Kinetic data were obtained from Figure Five B of [10]. Concentration of the substrates 2-oxoglutarate and NAD in the assay were fixed to: 1.0 mM and 16 μM. NADH concentration was 42 μM. Succinyl-CoA concentration were 0.0 (circle), 6.6 μM (up-triangle), and 13.2 μM (down-triangle). Solid lines are model fitting results from the data points represented by symbols. Experimental data were obtained in 0.08 mM potassium phosphate buffer at pH 7.2 and 30°C in Figures 2A-2D, and in 0.1 mM potassium phosphate at pH 7.2 and 22°C in Figures 2E-2F.

Qi et al. BMC Biochemistry 2011 12:53   doi:10.1186/1471-2091-12-53
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