Table 2.
Properties of active-site variants of thioredoxin.
| Protein | pKa of CXXC | Eo′ of CXXC (V) | Relative doubling time of complemented pdi1Δ yeast |
|---|---|---|---|
| Yeast PDI | ND | ND | 1.0 |
| Rat PDI | 6.7a | –0.180b | 1.8 ± 0.2c |
| CGPC Trx | 7.5d | –0.270e | NC |
| CGPS Trx | ND | – | 4.3 ± 0.5f |
| CGHC Trx | ND | –0.235e | 4.4 ± 0.8f |
| CVWC Trx | 6.2d | –0.230g | 3.8 ± 0.4f |
| CWGC Trx | 6.1d | –0.200g | 2.2 ± 0.2f |
ND, not determined; NC, no complementation.
a
Determined from the rate of inactivation by alkylation (34).
b
Determined from the equilibrium constant with GSH/GSSG and Trx (53).
c
Data from ref (49).
d
Determined by 13C-NMR spectroscopy for the state in which Asp26 and Cys35 are protonated (10).
e
Determined from the equilibrium constant of the thioredoxin reductase-catalyzed reaction with NADPH/NADP+ (48).
f
Data from ref (8).
g
Determined from the equilibrium constant of the thioredoxin reductase-catalyzed reaction with NADPH/NADP+ (8).