FIGURE 2.

Human bGP inhibition by H₂O₂ is due to the reversible formation of intramolecular disulfide bonds. a, recombinant bGP was first inhibited by H₂O₂ as in Fig. 1a. Oxidized bGP and non-treated bGP were subsequently and independently incubated with 5 mm DTT, 10 mm sodium arsenite (AsNaO₂), 5 mm GSH, or 10 μm thioredoxin for 10 min at 37 °C prior to activity measurement. Results are expressed as the percentage of the control. Red., reduced; Ox., oxidized. Data represent mean values of three independent experiments ± S.D., ***, p < 0.001 when compared with control; ###, p < 0.001 when two non-control groups are compared. b, recombinant bGP was inhibited by H₂O₂ as in Fig. 1c. Oxidized bGP and non-treated bGP were subsequently incubated with 5 mm DTT for 10 min at 37 °C prior to activity measurement. Reduction restored full activity of bGP. Results are expressed as the percentage of the control. Data represent mean values of three independent experiments ± S.D., ***, p < 0.001 when compared with control; ###, p < 0.001 when two non-control groups are compared.