O NMR spectroscopy-assisted bioactivity studies of the intermediates formed NaS and RSNO cross-linking reactions.

The cross-linking reaction between sulfide and -nitrosothiol moieties has been intensively investigated and thionitrite/thionitrous acid (SNO/HSNO) as well as nitrosopersulfide (SSNO) were reported to be the intermediates that could serve as reservoirs for nitric oxide (NO). However, debate still exists regarding the stability and biological activity of SNO/HSNO and SSNO. In order to investigate the chemical properties and biological activity of SNO and SSNO, we set out to re-characterize the reaction intermediates using UV-Vis and N NMR spectroscopy techniques, as well as a new O NMR approach. The effects of SNO and SSNO on cellular NO and cGMP levels were assessed cell culture experiments, and also the effects of SNO and SSNO on cell proliferation, migration, and capillary-like structure formation were evaluated with human umbilical vein endothelial cells (HUVEC). Through this work, the characteristic peaks and half-lives of SNO and SSNO were elucidated under various preparation conditions. The biological assays demonstrated that SSNO increased the cellular NO and cGMP levels and also facilitated cell proliferation, migration and stimulated angiogenesis, while in contrast SNO did not exhibit these effects.