Table 1.
Second-order rate constants for the reduction of selenoxides by TNB.
| Rate constants for the reduction of selenoxides by thiols (M−1 s−1) |
||||
|---|---|---|---|---|
| Selenoxide | TNBa | DTNBb | TNBa in the presence of 10 mM Gly | GSHc |
| SeMetO | (3.8±0.1)×104 | (3.8±0.1)×104 | – | k1=(1.2±0.4)×105 and k2=(1.5±0.2)×104 |
| SeTalO | (4.9±0.2)×103 | (4.8±0.2)×103 | – | (3.4±0.3)×103 |
| MSCO | (4.4±0.3)×103 | (4.9±0.6)×103 | (5.0±0.3)×103 | (2.5±0.4)×104 |
| NASMO | (1.2±0.1)×103 | (1.2±0.1)×103 | (2.5±0.2)×103 | (1.3±0.2)×103 |
| SePropO | (1.3±0.1)×103 | (1.31±0.06)×103 | – | (4.6±0.6)×102 |
a
Rate constant, k, for loss of thiol.
b
Rate constant, k, for formation of disulfide.
c
Rate constant designated k1 represents the reaction of the thiol with selenoxide to form a selenosulfide, with k2 representing reaction of the selenosulfide with a second thiol to produce the disulfide and selenoether.