Table 2.

Kinetic parameters for the sulfurtransferase activity of TSTD1, rhodanese, and MST

ND, not detected; n, Hill coefficient; S₂O₃²⁻ and SO₃²⁻, thiosulfate and sulfite, respectively.

Donor	Acceptor	Km donor	Km acceptor	kcat	n	kcat/Km donor	kcat/Km acceptor
		mm	mm	s−1		m−1 s−1	m−1 s−1
TSTD1
S2O32−	KCN	22 ± 3	0.27 ± 0.02	0.52		24	1.94 × 103
S2O32−	GSH	17 ± 1	11 ± 1	0.432	1.8 ± 0.2	25	39
GSSH	SO32−	ND	ND	ND		ND	ND
S2O32−	Cys	14 ± 2	13.7 ± 1.9	0.7	1.9 ± 0.1	50	51
S2O32−	Hcy	18 ± 1	10.7 ± 0.4	0.61	2.0 ± 0.1	34	57
S2O32−	Trx	22 ± 3	0.017 ± 0.002	0.116		5	6.8× 103
Rhodanesea
S2O32−	KCN	39.5 ± 2.5	29 ± 4	910		23 × 103	31 × 103
S2O32−	GSH	0.34 ± 0.05	21.0 ± 0.4	0.67	2.3 ± 0.2	2.0 × 103	0.03 × 103
GSSH	SO32−	0.450 ± 0.004	0.06 ± 0.01	389		0.86 × 106	6.5 × 106
MSTa
3MP	KCN	0.35 ± 0.06	6 ± 1	2.4		6.8 × 103	0.4 × 103
3MP	GSH	(20 ± 0.4)× 10−3	28 ± 2	0.3		15 × 103	0.01× 103
3MP	Trx	0.35 ± 0.06	(2.5 ± 0.4) × 10−3	1.3		3.7 × 103	520× 103

^a The values for rhodanese (14) and MST (13) were reported previously.