Selective trapping of SNO-BSA and GSNO by benzenesulfinic acid sodium salt: mechanistic study of thiosulphonate formation and feasibility as a protein -nitrosothiol detection strategy.

The conversion of -nitrosothiols to thiosulphonates by reaction with the sodium salt of benzenesulfinic acid (PhSONa) has been examined in detail with the exemplary substrates -nitrosoglutathione (GSNO) and -nitrosylated bovine serum albumin (SNO-BSA). The reaction stoichiometry (2:1, PhSONa:RSNO) and the rate law (first order in both PhSONa and RSNO) have been determined under mild acidic conditions (pH 4.0).