. Author manuscript; available in PMC: 2008 Nov 13.

Published in final edited form as: Biochemistry. 2007 Oct 20;46(45):13101–13108. doi: 10.1021/bi701550c

Table 1.

Steady State Kinetic Constants for Asp79 and Arg237 Mutants^a

	k_cat (s⁻¹)	K_{m, Pt} (μM)	K_{m, NAD} (μM)	k_cat/K_{m, Pt} (M⁻¹s⁻¹)
WT	2.42 (0.03)	55 (5)	35 (5)	6.5 (0.7) x 10⁴
D79A	0.0305 (0.0008)	1200 (100)	62 (3)	25 (2)
D79N	0.23 (0.01)	35 (5)	12 (1)	6.60 (0.90) x 10³
R237K	0.0126 (0.0006)	1.00 (0.10) x 10⁴	1000 (100)	1.25 (0.14)

All assays were performed at 25 °C, pH 7.25 in 100 mM MOPS. The steady state parameters k_cat and K_m,Pt were measured at saturating concentrations of NAD and the phosphite concentration was varied; K_m,NAD was determined by holding the phosphite concentration at a saturating level and varying the concentration of NAD. The errors given in parentheses are obtained from fitting to the Michaelis Menten equation.