TABLE 1.

Kinetic parameters for several substrates of THFA-DH from R. eutropha strain Bo^a

Substrate	Parameter
	Km (mM)	kcat/Km × 104 (M−1 s−1)	Ki (mM)
Primary alcohols
Ethanolb	3.1	3	—
n-Propanol	0.036	248	ND
n-Butanol	0.015	594	14.7
n-Pentanol	0.012	788	3.2
n-Hexanol	0.014	495	1.4
n-Heptanol	0.016	413	1.9
Aldehydes
Formaldehydeb	1.93	2.3	—
Acetaldehydeb	0.075	120	—
Propionaldehyde	0.057	159	8.2
Butyraldehyde	0.033	244	0.95
Pentanal	0.061	121	0.33
Secondary alcohols
2-Propanol	1.9	0.6	ND
2-Butanolb	1.12	3.1	—
2-Pentanol	0.12	99	8.6
2-Hexanol	0.08	167	1.6
2-Heptanol	0.058	204	1.0
2-Octanol	0.076	129	1.3
O-heterocyclic compounds
THF-2-alcohol	0.039	138	2.2
THF-3-alcohol	0.056	98	ND
Furfurylalcohol	0.025	185	1.9
Furfuraldehyde	0.147	16	11.0
Tetrahydropyran-2-alcohol	0.011	386	1.5
Diols
1,2-Butandiolb	1.03	5	—
1,3-Butandiolb	0.49	15	—
1,4-Butandiolb	0.25	30	—
PEG 6000b	0.55	7	—

^aActivities were determined with homogeneous THFA-DH (18.8 nM) in 75 mM MOPS-NaOH, pH 8.2, and 5 mM CaCl₂ under standard assay conditions with appropriate substrate concentrations. The apparent kinetic constants were determined by nonlinear curve fittings based on Michaelis-Menten kinetics. ND, not determined; —, no substrate inhibition detected under the conditions used. 

^bThe curves were fitted based on the model of Michaelis and Menten. All other curves were fitted based on the model of substrate inhibition as described in Materials and Methods.