OGDHC activity regulated by calcium and pH. (A) OGDHC activity as a function 2-oxoglutarate concentration with 1.0 mM NAD, 0.25 mM CoASH, and in the presence of 5 mM EGTA (circle) or 5 mM EGTA plus 5 mM CaCl2 (up-triangle)Kinetic data were obtained from Figure Three of . (B) OGDHC activity as a function free calcium concentration in the presence of 1.0 mM NAD, 0.25 mM CoA and 0.1 mM 2-oxoglurate. Kinetic data were obtained from Figure Four of . (C) OGCHC activity as a function of pH in the presence of 1.0 mM NAD, 0.25 mM CoASH with additions of 0.1 mM 2-oxoglurate plus 5 mM EGTA plus 5 mM CaCl2 (up-triangle) or plus 5 mM EGTA (circle), or with additions of 25 mM 2-oxoglutarate plus 5 mM EGTA plus 5 mM CaCl2 (square) or plus 5 mM EGTA (down-triangle). Kinetic data were from Table 2 in . Solid lines are model fitting results for the data points represented by symbols. Measurements were conducted at pH 7.0 and 30°C for Figure 3A and pH 6.8 and 30°C for Figure 3B and all in 50 mM MOPS buffer plus 1 mM dithiothreitol and with additions of appropriate substrates.
Qi et al. BMC Biochemistry 2011 12:53 doi:10.1186/1471-2091-12-53