TABLE 1.

Dehydrogenase, esterase, and GTN reductase activities of WT-, C302S-, and E268Q-ALDH2

Enzyme activities were determined as described under “Experimental Procedures” and are expressed as nmol × min⁻¹ × mg⁻¹. The activities of the mutants are also given relative to WT (WT = 100%). The data are the mean values ± S.E. of three independent experiments.

Enzyme activity	WT activity	C302S		E268Q
		Activity	Activity relative to WT	Activity	Activity relative to WT
			%		%
Dehydrogenase (pH 9.0)	4,042 ± 57	11.9 ± 2.2b	0.29 ± 0.06	56.1 ± 0.7b	1.39 ± 0.01
Dehydrogenase (pH 7.5)	2,690 ± 26	8.7 ± 1.2b	0.32 ± 0.05	23.5 ± 0.60b	0.88 ± 0.02
Esterase
−NAD	199.9 ± 0.5	0.71 ± 0.14b	0.36 ± 0.07	5.33 ± 0.39b	2.67 ± 0.20
+NAD	1,180 ± 31a	0.40 ± 0.14b	0.03 ± 0.01	0.64 ± 0.07b,a	0.06 ± 0.01
GTN reductase(1,2-GDN formation)
−NAD	1.21 ± 0.18	0.12 ± 0.03c	9.37 ± 1.18	1.57 ± 0.13	133 ± 11
+NAD	8.73 ± 0.09a	0.17 ± 0.06b	1.97 ± 0.65	0.29 ± 0.18b,d	3.36 ± 2.05

^a p < 0.0001 vs. no NAD.

^b p < 0.0001 vs. WT.

^c p < 0.001 vs. WT.

^d p < 0.005 vs. no NAD.