Detection and identification of S-nitrosylated proteins in endothelial cells

Nitric oxide performs some of its direct effects by the induction of various protein posttranslational modifications. Among them, S-nitrosylation of cysteines has gained increasing attention and has been postulated as a signaling mechanism. However, there are still many technical limitations for the detection and identification of this posttranslational modification in cell proteins, and some of them are directly related to the lability of the nitrosothiol bond. We describe protocols for applying a derivatization technique, the biotin switch, which substitutes the S-nitrosylation for a biotinylation in the detection and proteomic identification of S-nitrosylated proteins in intact cells.