title: Physiological thiols as promoters of glutathione oxidation and modifying agents in protein S-thiolation.
abstract: Glutathione is one of the most relevant antioxidants present in cells. It exerts its scavenging action through the involvement of efficient and ubiquitous enzymes. GSH on the other hand, because of its chemical features, can scavenge reactive oxygen species without the involvement of enzymatic systems. The study deals with the mobilization of GSH pool in a nonenzymatic antioxidant system by other physiological thiols (i.e., cysteine and cysteinyl-glycine), which are far more sensitive than GSH to oxidative conditions. These thiol compounds, in the presence of iron/EDTA, can promote oxygen activation through their oxidation to disulfides. GSH, through trans-thiolation reactions, can regenerate Cys and CysGly, which can then recycle, thus inducing a massive GSH oxidation. In these conditions, making use of bovine lens aldose reductase as a protein model, evidence is given that Cys and CysGly promote specific protein S-thiolation reactions. The possibility that GSH may be recruited in controlling cellular oxygen tension is considered.
authors.affiliation: Dipartimento di Fisiologia e Biochimica, Università di Pisa, via S. Maria 55, Pisa 56100, Italy.
authors.forename: Antonella
authors.initials: A
authors.lastname: Del Corso
authors.forename: Pier Giuseppe
authors.initials: PG
authors.lastname: Vilardo
authors.forename: Mario
authors.initials: M
authors.lastname: Cappiello
authors.forename: Ilaria
authors.initials: I
authors.lastname: Cecconi
authors.forename: Massimo
authors.initials: M
authors.lastname: Dal Monte
authors.forename: Daniela
authors.initials: D
authors.lastname: Barsacchi
authors.forename: Umberto
authors.initials: U
authors.lastname: Mura
mesh_terms: D000449:Aldehyde Reductase / Q000378:metabolism*; D003545:Cysteine / Q000737:chemistry / Q000378:metabolism; D004151:Dipeptides / Q000737:chemistry / Q000378:metabolism; D005978:Glutathione / Q000737:chemistry / Q000378:metabolism*; D008956:Models, Chemical; D010084:Oxidation-Reduction; D010100:Oxygen / Q000737:chemistry / Q000378:metabolism; D011499:Protein Processing, Post-Translational; D013438:Sulfhydryl Compounds / Q000737:chemistry / Q000378:metabolism*
chemical_list: D004151:Dipeptides; D013438:Sulfhydryl Compounds; C028505:cysteinylglycine; D000449:Aldehyde Reductase; D005978:Glutathione; D003545:Cysteine; D010100:Oxygen