Table 2.

Kinetic parameters of wild‐type and mutant enzymes of l‐AAO/MOG

Enzymea	Substrate	Oxidase			Monooxygenase			O/M ratiob
		k cat (s−1)	K m (mm)	k cat/K m (s−1·mm −1)	k cat (s−1)	K m (mm)	k cat/K m (s−1·mm −1)
Wild‐type	l‐Lys	0.80 ± 0.09	0.027 ± 0.003	30 ± 1	4.5 ± 0.1	0.061 ± 0.006	74 ± 5	0.18
	l‐Orn	1.5 ± 0.2	0.022 ± 0.004	68 ± 1.8	6.7 ± 0.6	0.033 ± 0.001	200 ± 10	0.22
	l‐Arg	0.41 ± 0.02	0.048 ± 0.001	8.5 ± 0.65	1.6 ± 0.2	0.067 ± 0.005	24 ± 1	0.26
D238A	l‐Lys	0.50 ± 0.03	0.61 ± 0.05	0.82 ± 0.09	2.7 ± 0.4	0.26 ± 0.02	10 ± 1	0.19
	l‐Orn	0.37 ± 0.05	0.45 ± 0.02	0.82 ± 0.10	0.29 ± 0.01	0.31 ± 0.01	0.94 ± 0.04	1.3
	l‐Arg	0.10 ± 0.02	0.41 ± 0.01	0.24 ± 0.06	2.8 ± 0.4	0.42 ± 0.04	6.7 ± 0.3	0.036
D238E	l‐Lys	2.3 ± 0.3	0.018 ± 0.006	130 ± 10	8.1 ± 0.6	0.043 ± 0.001	190 ± 10	0.28
	l‐Orn	0.58 ± 0.03	0.041 ± 0.004	14 ± 0.3	2.3 ± 0.2	0.061 ± 0.004	32 ± 2	0.25
D238F	l‐Lys	0.17 ± 0.01	0.049 ± 0.009	3.5 ± 0.2	0.80 ± 0.04	0.072 ± 0.003	11 ± 1	0.21
	l‐Arg	0.10 ± 0.01	0.080 ± 0.018	1.3 ± 0.1	1.2 ± 0.29	0.090 ± 0.004	13 ± 1	0.083

Reaction at 30 °C in 100 mm potassium phosphate (pH 7.0 for l‐Lys as a substrate) and borate–NaOH (pH 9.0 for l‐Arg and l‐Orn as substrates) using 1.0 μm l‐AAO/MOG (final concentration). For k _cat and K _m, means and 95% confidence limits of replicate assays are shown. ^a Activities of D238K, D238V, and D238N were not detected. The kinetic parameters of D238E for l‐Arg and D238F for l‐Orn were not determined because of undetectable activity. ^b Ratios of the oxidase/monooxygenase activities based on the k _cat values.