Nitric oxide DNIC formation

The formation of large amounts of GS-NO was observed during heating of solutions of B-DNIC with glutathione at pH 1.0 under aerobic conditions the concentration of GS-NO correlated with the formation of two GS-NO molecules per one iron atom (or four GS-NO molecules per each B-DNlC) (Figure 7.3b, line 2). It was reasonable to suppose that GS-NO formation is a result of oxidation of B-DNIC NO to nitrogen dioxide (NO2) and its subsequent hydrolysis to nitrous acid (HNO2) able to S-nitrosate thiols. However, an excursus into a textbook of chemistry corroborated the fact that this hydrolysis is terminated by the formation of nitrous and nitric acids of which only the former can initiate S-nitrosation of thiols by Equation 7.2. 

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