TABLE 2.
Reversibility of catalytic changes in rSULT1A1 after oxidative modification of the enzyme
|
Pretreatment of
rSULT1A1a
|
|||
|---|---|---|---|
| 5 mM DTT | 1 mM GSSG | DTT after GSSGb | |
| 2-Naphthol, 250 μM | 38.3 ± 4.7 | 50.2 ± 2.1c | 37.4 ± 1.5 |
| 4′-OH PCB 6, 100 μM | 0 | 37.3 ± 4.0 | 0 |
a
5 mM DTT and/or 1 mM GSSG was incubated with the enzyme at 25°C for 1 h before use in an assay for sulfotransferase activity. Data are the means and S.D. of three determinations.
b
One aliquot of GSSG-treated enzyme was further treated with DTT at 25°C for 1 h.
c
This value is statistically different from that for the group treated with 5 mM DTT alone (p < 0.05 by t test).