Distinct oxidative cleavage and modification of bovine [Cu- Zn]-SOD by an ascorbic acid/Cu(II) system: Identification of novel copper binding site on SOD molecule.

ABSTRACT: We investigated the combined effect of ascorbate and copper [Asc/Cu(II)] on the integrity of bovine [Cu-Zn]-superoxide dismutase (bSOD1) as a model system to study the metal catalyzed oxidation (MCO) and fragmentation of proteins. We found Asc/Cu(II) mediates specific cleavage of bSOD1 and generates 12.5 and 3.2kDa fragments in addition to oxidation/carbonylation of the protein. The effect of other tested transition metals, a metal chelator, and hydrogen peroxide on the cleavage and oxidation indicated that binding of copper to a previously unknown site on SOD1 is responsible for the Asc/Cu(II) specific cleavage and oxidation. We utilized tandem mass spectrometry to identify the specific cleavage sites of Asc/Cu(II)-treated bSOD1. Analyses of tryptic- and AspN-peptides have demonstrated th

SUBMITTER: Uehara H 

PROVIDER: S-EPMC4979071 | biostudies-literature | 2016 May

REPOSITORIES: biostudies-literature