Table 4 Kinetic parameters for the oxygenation of four different substrates by WT-hFMO3 and N61S variant.

From: Inactivation mechanism of N61S mutant of human FMO3 towards trimethylamine

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**

  1. a 28, b 38.
  2. *P < 0.05, **P < 0.01, ***P < 0.001 compared to WT-hFMO3, one-way ANOVA followed by Student-Newman-Keuls test.
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