Fig 6. Enzyme activities of E. coli and S. salinarum MDHs and ICDHs.

Enzymatic activity of E. coli (A, C) and S. salinarum (B, D) as a function of oxaloacetate or isocitrate concentration, respectively, in the presence of NaCl or GB. For all conditions, the buffer contained 32.5 mM Tris/HCl, pH 7.5. Nonlinear least-squared fits to the Michaelis-Menten equation are shown. See Table 1 for values of K_m, V_max, and the specificity constant, and S1 Data for underlying raw data. GB, glycine betaine; HCl, hydrogen chloride; ICDH, isocitrate dehydrogenase; MDH, malate dehydrogenase; NaCl, sodium chloride; Tris, tris(hydroxymethyl)aminomethane.