Table 4.

Kinetic parameters for the oxygenation of four different substrates by WT-hFMO3 and N61S variant.

Substrate	Enzyme	K m (μM)	k cat	k cat/K m
			(μM product/min/μM protein)	(min−1μM−1)
Trimethylamine	WT-hFMO3	21.7 ± 4.6	2.7 ± 0.2	0.12
	N61S	—	No activity	—
Methimazole	WT-hFMO3	14.9 ± 2.0	8.4 ± 0.9	0.56
	N61S	8652.1 ± 351.6***	7.1 ± 0.9	0.0008***
Benzydamine	WT-hFMO3	56.0 ± 8	9.0 ± 2a	0.16
	N61S	417.3 ± 74.6**	2.0 ± 0.2*	0.005*
Tamoxifen	WT-hFMO3	5.8 ± 1.1b	16.4 ± 0.6b	2.83
	N61S	14.8 ± 3.4*	0.44 ± 0.02***	0.03**

^{a 28}, ^{b 38}.

^*P < 0.05, **P < 0.01, ***P < 0.001 compared to WT-hFMO3, one-way ANOVA followed by Student-Newman-Keuls test.