Figure 1.

Ascorbate and an ascorbate-containing antioxidant mixture (Resiston) modify pH-dependent S-nitrosothiol formation. (A) GSNO formation after 3 h incubation of 500 µM GSH +1 µM NaNO₂ was pH-dependent. n = 3; p < 0.05. (B) 500 µM GSH, 5 µM NaNO₂ was incubated for 30 min in citrate buffer in the presence or absence (control) of 5 mM AA or Resiston. S-Nitrosothiols were detected by 2 °C (copper chloride cysteine) assay as described previously (Fang et al. 1998). (C) Five hundred micromoles of GSH and 5 µM NaNO₂ was incubated at pH 3.7 in citrate buffer in the presence or absence (control) of 5 mM AA or Resiston.