title: Glutaredoxins in thiol/disulfide exchange.
abstract: CONCLUSIONS
  Glutaredoxins (Grxs) are small oxidoreductases of the thioredoxin family of proteins regulating the thiol redox state of several proteins. Thereby, Grxs are key elements in redox signaling.
  
  
  BACKGROUND
  Redox signaling via protein thiols depends on reversible oxidative modifications induced mainly by reactive oxygen/nitrogen species and glutathione (GSH) in form of its oxidized disulfide or S-nitroso-glutathione. Grxs contribute to redox signaling by the catalysis of glutathionylation, de-glutathionylation, as well as reduction of disulfide bridges via two distinct enzymatic mechanisms. The dithiol mechanism utilizes both active site cysteines to reduce disulfides, whereas the monothiol mechanism utilizes only the N-terminal active site cysteine for the reduction of GSH mixed disulfides. The sphere of action of Grxs continues to grow with the recent identification of novel targets.
  
  
  RESULTS
  Because of limited methodological tools, the identification of new substrates for oxidoreductases in general is one of the biggest challenges in this research area.
  
  
  CONCLUSIONS
  With this review, we provide a condensed summary of the current knowledge of thiol/disulfide exchange reactions catalyzed by Grxs regarding the mechanistic, structural, and functional aspects. The latter will be of high importance for future research directions, gaining novel insights into redox signaling in general, and the role of Grxs in particular.
authors.affiliation: Institut für Biochemie und Molekularbiologie, Universitätsmedizin Greifswald, Ernst Moritz Arndt-Universität Greifswald, Greifswald, Germany.
authors.forename: Christopher Horst
authors.initials: CH
authors.lastname: Lillig
authors.forename: Carsten
authors.initials: C
authors.lastname: Berndt
mesh_terms: D002384:Catalysis; D004220:Disulfides / Q000737:chemistry / Q000378:metabolism*; D054477:Glutaredoxins / Q000737:chemistry / Q000378:metabolism*; D053858:Metabolic Networks and Pathways; D013438:Sulfhydryl Compounds / Q000737:chemistry / Q000378:metabolism*
chemical_list: D004220:Disulfides; D054477:Glutaredoxins; D013438:Sulfhydryl Compounds