Nitric oxide generation from S-nitrosoglutathione: New activity of indium and a survey of metal ion effects.

S-Nitrosothiols (RSNOs) such as S-nitrosoglutathione (GSNO) are known to produce nitric oxide (NO) through thermal, photolytic, and metal ion-promoted pathways, which has led to their increasing use as exogenous sources of therapeutic NO. Despite the burgeoning NO release applications for RSNOs, their susceptibility to metal-promoted decomposition has rarely been examined in a uniform manner through the specific measurement of NO release. In this study, the ability of various transition and post-transition metal ions to promote NO release from GSNO was surveyed by chemiluminescence-based NO detection. Substantial NO formation (>10-fold increase relative to GSNO baseline) was detected after the addition of Cu, Au, Pd, Pt, and V. Modest increases were observed in the cases of Co, Hf, Fe, Fe, Mn, Hg, Ni, Ag, Sn, and Zr, while no effect was evident for Al, Cr, Pb, Sc, and Zn. It was further observed that In compounds initiate the apparent NO-forming decomposition of GSNO, while In and In are inactive, indicating that In exerts a previously unknown effect on GSNO.