Table 1 Kinetic parameters for AtALDH10A8 and AtALDH10A9^a.

Substrate/coenzyme	V_max^b	AtALDH10A8			V_max	AtALDH10A9
Substrate/coenzyme	V_max^b	K_m	K_is	k_cat/K_m	V_max	K_m	K_is	k_cat/K_m
ABAL	1.6 ± 0.3	25.1 ± 2.5	55.7 ± 26.0	0.06	9.5 ± 1.5	460 ± 65	2.6E03 ± 7.5E02	0.02
NAD⁺	0.8 ± 0.1	20.8 ± 3.0	1.2E06 ± 6.4E05	0.04	4.2 ± 0.5	73.6 ± 16.4	9.5E06 ± 1.5E06	0.06
APAL	15.8 ± 1.4	14.4 ± 2.7	5.5 ± 0.3	1.03	15 ± 3.3	17.3 ± 4.1	1.9E04 ± 5.8E03	0.82
NAD⁺	3.6 ± 0.6	13.2 ± 1.5	5.4E05 ± 5.3E03	0.26	13.4 ± 3	86 ± 16	6.1E06 ± 3E05	0.15

Initial rate of NAD⁺ reduction was plotted against increasing ABAL, APAL or NAD⁺ concentration and the data were fit to the appropriate Michaelis-Menten equation. pH of assays were adjusted to 8.5 and 9.5 for AtALDH10A8 and AtALDH10A9 respectively. Each value represents the mean (± SE) of three enzyme preparations.
^aNAD⁺ dependence was estimated in the presence of 7 and 30 μM APAL and 40 and 900 μM ABAL for AtALDH10A8 and AtALDH10A9, respectively to minimize substrate inhibition; therefore, the values in this table are apparent. Similarly, ABAL and APAL dependence assays were measured at 100 μM NAD⁺ for AtALDH10A8 and 500 μM NAD⁺ for AtALDH10A9. All kinetic curves are shown in Supplementary Figure S4.
^bV_max (μmol min⁻¹ mg⁻¹ protein), K_m (μM), catalytic efficiency (k_cat/K_m, μM⁻¹ s⁻¹) and substrate inhibition constant (K_is, μM) are shown for each substrate or coenzyme.

Quick links

Search