Novel Peptide Ion Chemistry Associated with Gold (I) Cationization: Preferential Cleavage at Lysine Residues.

ABSTRACT: Novel peptide ion chemistry associated with gold (I) cationization is described. Cation switching ion/ion reactions, involving gold dichloride reagent anion, [AuCl₂]^-, are used to replace protons with a gold (I) cation on a polypeptide. Collision induced dissociation of aurated, lysine-containing peptides results in the elimination of gold hydride and ammonia, generating a [M - H - NH₃]⁺ oxidized species. The oxidized product is likely a cyclic iminium ion. This fragmentation pathway is specific to lysine side-chains as polypeptides containing arginine or histidine in the absence of lysine were not observed to form the oxidized product. While oxidation can occur on N-terminal, internal, and C-terminal lysine residues, it is observed to a lesser e

SUBMITTER: Foreman DJ 

PROVIDER: S-EPMC5985815 | biostudies-literature | 2018 Apr

REPOSITORIES: biostudies-literature