期刊
JOURNAL OF BIOLOGICAL CHEMISTRY
卷 278, 期 17, 页码 14607-14613出版社
AMER SOC BIOCHEMISTRY MOLECULAR BIOLOGY INC
DOI: 10.1074/jbc.M210434200
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资金
- NIA NIH HHS [AG15885] Funding Source: Medline
Glutaredoxin (GRx, thioltransferase) is implicated in cellular redox regulation, and it is known for specific and efficient catalysis of reduction of protein-S-S-glutathione-mixed disulfides (protein-SSG) because of its remarkably low thiol pK(a) (approximate to3.5) and its ability to stabilize a catalytic S-glutathionyl intermediate (GRx-SSG). These unique properties suggested that GRx might also react with glutathione-thiyl radicals (GS(.)) and stabilize a disulfide anion radical intermediate (GRx-SSG(.)), thereby facilitating the conversion of GS(.) to GSSG or transfer of GS(.) to form protein-SSG. We found that GRx catalyzes GSSG formation in the presence of GS-thiyl radical generating systems (Fe2+/ADP/H2O2 + GSH or horseradish peroxidase/H2O2 + GSH). Catalysis is dependent on 02 and results in concomitant superoxide formation, and it is distinguished from glutathione peroxidase-like activity. With the horseradish peroxidase system and [S-35]GSH, GRx enhanced the rate of GS-radiolabel incorporation into GAPDH. GRx also enhanced the rate of S-glutathionylation of glyceraldehyde-3-phosphate dehydrogenase with GSSG or S-nitrosoglutathione, but these glutathionyl donors were much less efficient. Both actin and protein-tyrosine phosphatase-1B were superior substrates for GRx-facilitated S-glutathionylation with GS-radical. These studies characterize GRx as a versatile catalyst, facilitating GS-radical scavenging and S-glutathionylation of redox signal mediators, consistent with a critical role in cellular regulation.
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