Oxidative stress induced S-glutathionylation and proteolytic degradation of mitochondrial thymidine kinase 2.

ABSTRACT: Protein glutathionylation in response to oxidative stress can affect both the stability and activity of target proteins. Mitochondrial thymidine kinase 2 (TK2) is a key enzyme in mitochondrial DNA precursor synthesis. Using an antibody specific for glutathione (GSH), S-glutathionylated TK2 was detected after the addition of glutathione disulfide (GSSG) but not GSH. This was reversed by the addition of dithiothreitol, suggesting that S-glutathionylation of TK2 is reversible. Site-directed mutagenesis of the cysteine residues and subsequent analysis of mutant enzymes demonstrated that Cys-189 and Cys-264 were specifically glutathionylated by GSSG. These cysteine residues do not appear to be part of the active site, as demonstrated by kinetic studies of the mutant enzymes. Treatment of isolat

SUBMITTER: Sun R 

PROVIDER: S-EPMC3397856 | biostudies-literature | 2012 Jul

REPOSITORIES: biostudies-literature