Characteristics of high energy collision-induced dissociation tandem mass spectra of polycyclic aromatic hydrocarbon diolepoxide adducted peptides

Abstract

Polycyclic aromatic hydrocarbon (PAH) diolepoxides are known to covalently modify serum albumin and hemoglobin. Mass spectrometric techniques have proven quite useful in the characterization of the site of adduction on these proteins. To facilitate the study of PAH diolepoxide adducted peptides, model peptide adducts of benzo[a]pyrene- rans-7,8-dihydrodiol-9,10-epoxide [ anti-B aP(9,10)DE] and benzo[ a]anthracene- trans-8,9-dihydrodiol-10,11-epoxide [anti-B aA(10,11)DE] have been synthesized for the purpose of studying their high energy collision-induced dissociation tandem mass spectra. These spectra are dominated by ions produced from cleavage of the peptide—adduct bond with charge retention by the adducting moiety. Such ions allow for the facile identification of adducted peptides in a mixture by use of neutral loss scans. The peptide sequence can still be deduced from the data in most cases, and the site of adduction can be determined. For those peptide—adducts in which this is not possible, a charged derivative placed at the N-terminus simplifies the peptide fragmentation pattern and makes the spectrum more interpretable.