One- and two-electron oxidation of thiols: mechanisms, kinetics and biological fates.
The oxidation of biothiols participates not only in the defense against oxidative damage but also in enzymatic catalytic mechanisms and signal transduction processes. Thiols are versatile reductants that react with oxidizing species by one- and two-electron mechanisms, leading to thiyl radicals and sulfenic acids, respectively. These intermediates, depending on the conditions, participate in further reactions that converge on different stable products. Through this review, we will describe the biologically relevant species that are able to perform these oxidations and we will analyze the mechanisms and kinetics of the one- and two-electron reactions. The processes undergone by typical low-molecular-weight thiols as well as the particularities of specific thiol proteins will be described, including the molecular determinants proposed to account for the extraordinary reactivities of peroxidatic thiols. Finally, the main fates of the thiyl radical and sulfenic acid intermediates will be summarized.
a Departamento de Bioquímica , Facultad de Medicina, Universidad de la República , Montevideo , Uruguay .|b Center for Free Radical and Biomedical Research , Universidad de la República , Montevideo , Uruguay , and.
Madia
M
Trujillo
b Center for Free Radical and Biomedical Research , Universidad de la República , Montevideo , Uruguay , and.|c Laboratorio de Enzimología, Facultad de Ciencias , Universidad de la República , Montevideo , Uruguay.
Beatriz
B
Alvarez
a Departamento de Bioquímica , Facultad de Medicina, Universidad de la República , Montevideo , Uruguay .|b Center for Free Radical and Biomedical Research , Universidad de la República , Montevideo , Uruguay , and.
Rafael
R
Radi
D000818:Animals; D001419:Bacteria; D056890:Eukaryota; D005609:Free Radicals; D006801:Humans; D007700:Kinetics; D010084:Oxidation-Reduction; D013434:Sulfenic Acids; D013438:Sulfhydryl Compounds / Q000737:chemistry / Q000378:metabolism*
D005609:Free Radicals; D013434:Sulfenic Acids; D013438:Sulfhydryl Compounds
Cysteine; peroxidases sulfenic acid; thiol; thiyl radical