The –SH Protection Method for Determining Accurate K_d Values for Enzyme-Coenzyme Complexes of NAD⁺-Dependent Glutamate Dehydrogenase and Engineered Mutants: Evidence for Nonproductive NADPH Complexes

Table 2

Comparison of dissociation constants of wild-type and mutant enzymes for different coenzymes.

	𝐾𝑑NAD+ (mM)	𝐾𝑑NADH (mM)	𝐾𝑑NADPH (mM)	𝐾𝑑NADPH/𝐾𝑑NADH
Wild-type	0.335 ± 0.017	0.024 ± 0.001	0.023 ± 0.001	0.96
F238S	6.62 ± 0.25	0.232 ± 0.056	1.30 ± 0.056	5.6
P262S	2.84 ± 0.22	0.052 ± 0.004	0.375 ± 0.03	7.2
F238S/P262S	4.30 ± 0.38	0.253 ± 0.021	0.526 ± 0.045	2.1
D263K	2.02 ± 0.21	0.130 ± 0.012	0.228 ± 0.021	1.75