The mobile proton in biomolecular clusters: Tripeptides and vanillic acid

- We investigated the biomolecular cluster ions formed in a supersonic jet by resonance enhanced multi photon ionization.
- Fragmentation of the biomolecular cluster ions leads to the formation of protonated peptide ions.
- It is shown that the ionization of the cluster is described by a dissociative proton transfer to the N-terminal end of the peptide by isotopic labeling.
- Fragmentation of the protonated peptides is conducted through a proton chain walk.