. Author manuscript; available in PMC: 2011 Apr 27.

Published in final edited form as: Biochemistry. 2010 Apr 27;49(16):3487–3498. doi: 10.1021/bi100294m

Table 5.

Kinetic Parameters for rS-HPCDH3 and rR-HPCDH1 catalyzed oxidation of 2-butanol^a

Substrate	K_m (mM)	V_m_ax (units/mg)	k_cat (s^-1)	k_cat/K_m (M^-1 s^-1)	Change in k_cat (x-fold)	Change in K_m (x-fold)	enantioselectivity (E)
rS-HPCDH3

(R)-2-butanol	68 ± 3	2.2 ± 0.03	1.0	14.8	1.0	1.0	0.16
(S)-2-butanol	28 ± 2	5.8 ± 0.07	2.6	92.8	2.6	0.4	6.3

rR-HPCDH1

(R)-2-butanol	220 ± 10	3.77 ± 0.06	1.9	8.69	1.0	1.0	0.33
(S)-2-butanol	350 ± 50	18.8 ± 0.9	9.3	26.4	5.0	1.6	3.0

^aAll assays were performed in triplicate at 30 °C with fixed concentrations of NAD⁺ (10 mM). Assays of 2-butanol oxidation catalyzed by rS-HPCDH3 and rR-HPCDH1 contained 25 and 21 μg of enzyme, respectively. Apparent kinetic constants were determined by fitting experimental data to the standard form of the Michaelis-Menten equation. Apparent V_max and K_m values are reported as means ± standard deviations. All other values are reported as means only. Enantioselectivity was defined as (k_cat/K_m)_R_-enantiomer/(k_cat/K_m)_S_-enantiomer for (R)-2-butanol oxidation and as (k_cat/K_m)_S_-enantiomer/(k_cat/K_m)_R_-enantiomer for (S)-2-butanol oxidation.