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 Cu2+ , Au3+ , Pd2+ , Pt2+ , and V3+ . Modest increases were observed in the cases of Co2+ , Hf4+ , Fe2+ , Fe3+ , Mn2+ , Hg2+ , Ni2+ , Ag+ , Sn2+ , and Zr4+ , while no effect was evident for Al3+ , Cr3+ , Pb2+ , Sc3+ , and Zn2+ . It was further observed that In+ compounds initiate the apparent NO-forming decomposition of GSNO, while In0 and In3+ are inactive, indicating that In+ exerts a previously unknown effect on GSNO.