Table 2.

Apparent steady-state kinetic parameters of LSD4 for different substrates^a

Substrate	Enzyme	$k_{\text{cat}}^{app}$	$K_{\text{M}}^{app}$	$k_{\text{cat}}^{app}/K_{\text{M}}^{app}$	$k_{\text{cat}}$b	$K_{\text{M}\_\text{O}2}$	$k_{\text{cat}}/K_{\text{M}\_\text{O}2}$
		s−1	μM	× 105 s−1 M−1	s−1	μM	× 105 s−1 M−1
lignostilbene	WT	18 ± 1	13 ± 1	14 ± 1	39 ± 2	320 ± 20	1.2 ± 0.1
	S283A	15.3 ± 0.4	10 ± 1	15 ± 1	20 ± 1	400 ± 30	0.50 ± 0.04
	S283F	0.14 ± 0.01	8.5 ± 0.7	0.16 ± 0.02	n.d.c	n.d.	n.d.
DCA-S	WT	11 ± 1	12 ± 1	9 ± 1	26 ± 1	220 ± 20	1.2 ± 0.1
	S283A	4.1 ± 0.1	4.6 ± 0.5	9 ± 1	7.8 ± 0.6	410 ± 60	0.19 ± 0.03
	S283F	0.035 ± 0.001	2.7 ± 0.5	0.13 ± 0.05	n.d.	n.d.	n.d.

^aExperiments were performed using HEPES (I = 0.1 M), pH 7.5, at 25 °C. Parameters were calculated using a minimum of 20 data points at various substrate concentrations. Apparent parameters for stilbene substrates were obtained using air-saturated buffer. Parameters obtained for O₂, including k_cat values, were determined using 100 μM lignostilbene or DCA-S.

^bCalculated from saturating amounts of O₂ and stilbene.

^cNot determined.