Table 2.

Compilation of all rate constants observed in the thiol kinetic profiling experiments with the indicated oxidant^a

Oxidantb	k i (s−1)	C9A SpCstR	C9A/N55A SpCstR	SmCstR	EfCstR
Tetrathionate	k 1	0.036 ± 0.004	0.146 ± 0.004	0.0033 ± 0.0002	n.d.c
H2O2	k 1	0.0135 ± 0.0005	0.0079 ± 0.0002	n.d.	n.d.
	k2	0.0079 ± 0.0004	0.0069 ± 0.0003
Cystine		No reactiond	No reaction	No reaction	No reaction
GSSG	k 1	1.35 ± 0.01 × 10−4	1.35 ± 0.02 × 10−4	n.d.	n.d.
	k2	4.7 ± 0.1 × 10−4	3.8 ± 0.1 × 10−4
	k 3	1.18 ± 0.03 × 10−4	2.7 ± 0.1 × 10−4
CysSSH	k 1	0.037 ± 0.002	0.039 ± 0.002	0.044 ± 0.002	0.033 ± 0.001
	k2	0.0014 ± 0.0002	0.00062 ± 0.00007	1.1 ± 0.1 × 10−5	0.00126 ± 0.00004
	k -2	0.0016 ± 0.0002	0.00024 ± 0.00006	≤10−6	≤10−6
	k 3	4.2 ± 0.6 × 10−5	4.2 ± 1.3 × 10−5	3 ± 2 × 10−5	8.4 ± 2.7 × 10−6
	k 4	1.01 ± 0.07 × 10−4	6.8 ± 1.5 × 10−5	4 ± 2 × 10−5	0.02 ± 0.01 e
	k -4	≤10−6	≤10−6	≤10−6	0.02 ± 0.01 e
	k 4’	≤10−6	0.0012 ± 0.0007	≤10−6	≤10−6

^aAll oxidants were present at a 20-fold molar excess of CstR protomer (10-fold excess over Cys thiol). ^btetrathionate, refer to Supplementary Figure S9; H₂O₂, refer to Figure 5; cystine, refer to Supplementary Figure S10; GSSG, refer to Figure 7; CysSSH, refer to Figure 6. ^cn.d., not determined. ^dNo observable product formation over the course of a 3 h reaction. A sequential kinetic model was used to obtain k_i for H₂O₂ and GSSG, while a reversible bifurcated kinetic model was used for CysSSH. See text for additional details. ^eFitted bound to the same value according to the final product distribution.