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

Abstract 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 2+ , Au 3+ , Pd 2+ , Pt 2+ , and V 3+ . Modest increases were observed in the cases of Co 2+ , Hf 4+ , Fe 2+ , Fe 3+ , Mn 2+ , Hg 2+ , Ni 2+ , Ag + , Sn 2+ , and Zr 4+ , while no effect was evident for Al 3+ , Cr 3+ , Pb 2+ , Sc 3+ , and Zn 2+ . It was further observed that In + compounds initiate the apparent NO-forming decomposition of GSNO, while In 0 and In 3+ are inactive, indicating that In + exerts a previously unknown effect on GSNO.