TABLE 4.

Inactivation parameters of n-butanol pathway enzymes^a

Enzyme	Inactivation parameterb
	70°C				60°C
	β	k1 (10−3 min−1)	k2 (10−3 min−1)	t1/2 (min)	β	k1 (10−3 min−1)	k2 (10−3 min−1)	t1/2 (min)
Thl		3.36 ± 0.65		206		2.12 ± 0.34		327
Hbd		0.20 ± 0.08		3,470		0.10 ± 0.09		6,930
Crt		4.17 ± 1.06		166		0.10 ± 0.12		6,930
Ter		4.59 ± 0.48		151		0.32 ± 0.08		2,170
Badc	0.70 ± 0.06	315 ± 174	6.88 ± 1.71	52.1	0.43 ± 0.04	204 ± 38	5.49 ± 2.55	9.49
Bdhd	0.13 ± 0.01	385 ± 21	60.5 ± 3.2	2.18	0.58 ± 0.03	370 ± 65	10.6 ± 1.4	16.9
Ctherm-AdhEd		1169 ± 178		0.59		2.52 ± 0.06		275
X514-AdhEd	0.68 ± 0.05	622 ± 225	32.8 ± 3.7	11.0		1.03 ± 0.08		673

^a

Enzyme inactivation data were fit to a two-step enzyme inactivation model or a simple first-order inactivation model. The two-step enzyme inactivation mechanism or one-step inactivation model were calculated by using the following equations:

$$y(t)=[1+\beta k_1/(k_2-k_1)]\hspace{0.17em}\exp (-k_{1}t)-\beta k_1/(k_2-k_1)\hspace{0.17em}\hspace{0.17em}\exp (-k_{2}t)$$

and

$$y(t)=\exp (-k_{1}t)$$

^bUncertainties represent one standard error. t_1/2, half-life.

^cWith butyryl-CoA as the substrate.

^dWith butyraldehyde as the substrate.