Routes for Formation of S-Nitrosothiols in Blood

S-nitrosothiols (RSNO) are involved in post-translational modifications of many proteins analogous to protein phosphorylation. In addition, RSNO have many physiological roles similar to nitric oxide ((NO)-N-aEuro cent), which are presumably involving the release of (NO)-N-aEuro cent from the RSNO. However, the much longer life span in biological systems for RSNO than (NO)-N-aEuro cent suggests a dominant role for RSNO in mediating (NO)-N-aEuro cent bioactivity. RSNO are detected in plasma in low nanomolar levels in healthy human subjects. These RSNO are believed to be redirecting the (NO)-N-aEuro cent to the vasculature. However, the mechanism for the formation of RSNO in vivo has not been established. We have reviewed the reactions of (NO)-N-aEuro cent with oxygen, metalloproteins, and free radicals that can lead to the formation of RSNO and have evaluated the potential for each mechanism to provide a source for RSNO in vivo.