TABLE 3.

Kinetic parameters of substituted SorAB sulfite dehydrogenases, SDH^Y236F, SDH^R55M, and SDH^H57A

Square brackets denote values for which insufficient data points could be obtained due to the high sulfite concentrations needed to achieve saturating sulfite concentrations.

pH	Kinetic parameters
	Km(sulfite)	kcat	kcat/Km(sulfite)
	mm	s-1	m-1 s-1
SDH Y236F
6.0	0.004 ± 0.6 × 10-3	36.8 ± 1.5	8.42 × 106
6.5	0.007 ± 0.6 × 10-3	41.6 ± 0.8	5.60 × 106
7.0	0.026 ± 0.0032	51.8 ± 1.5	1.97 × 106
7.5	0.042 ± 0.0041	48.3 ± 1	1.14 × 106
8.0	0.114 ± 0.0135	53.4 ± 1.6	4.61 × 105
8.5	0.332 ± 0.0447	58.3 ± 2.4	1.73 × 105
9.0	1.155 ± 0.1166	64 ± 2	5.45 × 104
9.5	4.456 ± 0.6693	52.7 ± 3.5	1.16 × 104
10.0	15.487 ± 2.8	44.8 ± 4.7	2.84 × 103
SDH R55M
5.8	0.812 ± 0.114	70.5 ± 2.4	8.68 × 104
6.2	1.087 ± 0.26	64.0 ± 3.9	5.89 × 104
6.6	1.63 ± 0.39	64.0 ± 4.3	3.93 × 104
7.0	1.95 ± 0.49	66.3 ± 4.2	3.4 × 104
7.5	3.62 ± 0.57	68.3 ± 3.3	1.89 × 104
7.9	8.17 ± 1.37	73.4 ± 4.8	8.98 × 103
8.3	[33.27 ± 7.5]	[109.88 ± 15.04]	[3.3 × 103]
SDH H57A
6.0	0.667 ± 0.12	238.8 ± 16.5	3.58 × 105
6.5	0.29 ± 0.003	226.5 ± 7.6	7.82 × 105
7.0	0.189 ± 0.001	214.5 ± 3.7	1.13 × 106
7.5	0.22 ± 0.002	220.5 ± 5.6	1.01 × 106
8.0	0.27 ± 0.003	214.6 ± 6	7.99 × 105
8.5	0.452 ± 0.06	222.4 ± 9.9	4.92 × 105
9.0	1.46 ± 0.16	192.5 ± 7.5	1.32 × 105
9.5	12.2 ± 3.4	148.4 ± 25.8	1.22 × 104