Quantification of oxidative posttranslational modifications of cysteine thiols of p21ras associated with redox modulation of activity using isotope-coded affinity tags and mass spectrometry.

ABSTRACT: p21ras GTPase is the protein product of the most commonly mutated human oncogene and has been identified as a target for reactive oxygen and nitrogen species. Posttranslational modification of reactive thiols, by reversible S-glutathiolation and S-nitrosation, and potentially also by irreversible oxidation, may have significant effects on p21ras activity. Here we used an isotope-coded affinity tag (ICAT) and mass spectrometry to quantitate the reversible and irreversible oxidative posttranslational thiol modifications of p21ras caused by peroxynitrite (ONOO(-)) or glutathione disulfide (GSSG). The activity of p21ras was significantly increased after exposure to GSSG, but not to ONOO(-). The results of LC-MS/MS analysis of tryptic peptides of p21ras treated with ONOO(-) showed that ICAT lab

SUBMITTER: Sethuraman M 

PROVIDER: S-EPMC1855198 | biostudies-literature | 2007 Mar

REPOSITORIES: biostudies-literature