. Author manuscript; available in PMC: 2013 May 20.

Published in final edited form as: Biochemistry. 2011 Jun 10;50(26):5870–5882. doi: 10.1021/bi200107n

Table 2.

The kinetic parameters of wild-type SmTGR, Cys28Ala, Cys31Ala, Cys28Ala/Cys31Ala, and Cys31Ser reacting with the substrates, DTNB (DTNB activity), GSSG (GR activity), and Trx (TrxR activity) in the presence of saturating NADPH (100 μM).

	DTNB activity (k_cat, s⁻¹)	% of WT	K_m for DTNB (μM)
WT	16 ± 0.6	-	319 ± 47
Cys28Ala	6 ± 0.2	38	230 ± 22
Cys31Ala	6 ± 0.1	38	43 ± 5
Cys28Ala/Cys31Ala	8 ± 0.2	50	406 ± 25
Cys31Ser	16 ± 0.8	100	169 ± 24
	GR activity (k_cat, s⁻¹)	% of WT	K_m for GSSG (μM)
WT	19.4 ± 1.2	-	42 ± 6
Cys28Ala	0.7 ± 0.1	4	16 ± 0.2
Cys31Ala	3.5 ± 0.1	18	13 ± 2
Cys28Ala/Cys31Ala	0.6 ± 0.1	3	23 ± 4
Cys31Ser	25± 1.5	129	189 ± 27
	TrxR activity (k_cat, s⁻¹)	% of WT	K_m for Trx (μM)
WT	19 ± 0.2	-	8 ± 0.3
Cys28Ala	14 ± 1.4	74	22 ± 4.5
Cys31Ala	19 ± 0.4	100	8 ± 0.6
Cys28Ala/Cys31Ala	15± 1.5	79	19 ± 4
Cys31Ser	20 ± 0.4	105	8 ± 0.5