Collisionally-Activated Dissociation of Peptides with a Disulfide Bond: Confirmation of the Mobile-Proton Model Based Explanation

• Published in: Mass spectrometry letters Vol. 1; no. 1; pp. 5 - 8
• Main Authors: Lee, Youn-Jin, Oh, Han-Bin
• Format: Journal Article
• Language: Korean
• Published: 30.12.2010
• Subjects: Tandem mass spectrometry; Collisionally activated dissociation (CAD); Mobile proton model; Peptides; Disulfide bond
• ISSN: 2233-4203; 2093-8950

In the present study, collisionally-activated dissociation (CAD) experiments were performed under low energy collision conditions in six peptides containing a disulfide bond. Fragments produced as a result of the cleavage of a disulfide bond were obtained after CAD in four peptides (bactenecin, TGF-$\alpha$, cortistantin, and linearly linked peptide, Scheme 1) with basic amino acid residues. In contrast, the CAD analysis of two peptides with no basic residue (oxytocin and tocinoic acid) rarely produced fragments indicative of cleavage of a disulfide bond. These results are consistent with the mobile proton model suggested by the McLuckey and O'air groups (ref. 22 and 23); nonmobile protons sequestered at basic amino acid residues appear to promote the cleavage of disulfide bonds.