Description: Nitric oxide (NO), generated by cell type-specific NO- synthase (NOS) isoforms, is a freely diffusible intercellular messenger that functions in target cells in NOS-dependent signaling. S-nitrosylation of cysteine thiols in proteins by the highly labile NO radical has been identified as an important effector of NO-related bioactivity both in NOS- containing cells and intercellular signaling. Most cells contain low levels of nitrosylated proteins that are thought to be regulated by S-nitrosylation and denitrosylation. S-nitrosylation of proteins serves as a ubiquitous post- translational modification that dynamically regulates a broad functional spectrum of proteins. The majority of these proteins are regulated by S-nitrosylation on a single critical cysteine residue within an acidic/basic or hydrophobic structural motif that may also be subject to oxygen- or glutathione-dependent modification. NO- sensitive ion channels including the cardiac and skeletal muscle ryanodine receptor (RyR1), N-methyl-D-aspartate receptor (NMDAR) complex, cyclic-nucleotide gated ion channel, are modulated by S-nitrosylation. S-nitrosylation of capsase-3 inhibits apoptosis signaling. S-nitrosylation activates matrix metalloproteinase-9 (MMP-9) and induces neuronal apoptosis. The small G-protein p21Ras and Jun kinase are regulated by S-nitrosylation. The activity of transcription factors such as NFB, c-jun, and c-fos is modulated by S-nitrosylation. In addition, the formation of S-nitrosylated glutathione (GSNO) has been proposed to be one of the major storage forms of NO in vivo.
SNO-Cys-BSA protein conjugate was prepared by coupling Cysteine to BSA followed by nitrosylation of cysteines.