title: Chemical methods for the direct detection and labeling of S-nitrosothiols.
abstract: CONCLUSIONS
  Posttranslational modification of proteins through phosphorylation, glycosylation, and oxidation adds complexity to the proteome by reversibly altering the structure and function of target proteins in a highly controlled fashion.
  
  
  BACKGROUND
  The study of reversible cysteine oxidation highlights a role for this oxidative modification in complex signal transduction pathways. Nitric oxide (NO), and its respective metabolites (including reactive nitrogen species), participates in a variety of these cellular redox processes, including the reversible oxidation of cysteine to S-nitrosothiols (RSNOs). RSNOs act as endogenous transporters of NO, but also possess beneficial effects independent of NO-related signaling, which suggests a complex and versatile biological role. In this review, we highlight the importance of RSNOs as a required posttranslational modification and summarize the current methods available for detecting S-nitrosation.
  
  
  RESULTS
  Given the limitations of these indirect detection methods, the review covers recent developments toward the direct detection of RSNOs by phosphine-based chemical probes. The intrinsic properties that dictate this phosphine/RSNO reactivity are summarized. In general, RSNOs (both small molecule and protein) react with phosphines to yield reactive S-substituted aza-ylides that undergo further reactions leading to stable RSNO-based adducts.
  
  
  CONCLUSIONS
  This newly explored chemical reactivity forms the basis of a number of exciting potential chemical methods for protein RSNO detection in biological systems.
authors.affiliation: Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, USA.
authors.forename: Erika
authors.initials: E
authors.lastname: Bechtold
authors.forename: S Bruce
authors.initials: SB
authors.lastname: King
mesh_terms: D000818:Animals; D006801:Humans; D009569:Nitric Oxide / Q000737:chemistry; D015538:Nitrosation; D026403:S-Nitrosothiols / Q000737:chemistry*
chemical_list: D026403:S-Nitrosothiols; D009569:Nitric Oxide