Skip to main content
. 2006 Nov 28;400(Pt 3):521–530. doi: 10.1042/BJ20060843

Figure 3. pH-dependence of the steady-state rate constant kcat for K178A and T244S GAPNs.

Figure 3

pH-dependence of kcat was studied over the pH range 5.25–8.75 for T244S GAPN or 5.25–9.00 for K178A GAPN with a mixed reaction buffer consisting of 120 mM Tricine, 30 mM imidazole and 30 mM ethanoic acid at a constant ionic strength of 0.15 M. The other experimental conditions were as follows: 0.15 mM D,L-G3P, 1 mM NADP and 1.65 μM K178A GAPN; and 1.5 mM D,L-G3P, 0.03 mM NADP and 0.5 μM T244S GAPN. Data for T244S (▲) and K178A (●) GAPNs were best fitted by non-linear regression analysis against a single pKapp model, identified by the best-fit theoretical curves (solid line and dotted line respectively). S.E.M. on each experimental point was less than 5%.