Formation of Polymolecular Associates of Short-Chain Peptides With Copper Ions Under Electrospray Ionization Conditions

The ionization processes of short-chain peptides in the presence of cationizing agents – metal salts – have been studied. The electrospray ionization method with mass spectrometric detection was used in this work. The mass spectrometric study demonstrated the ability of peptides to form cluster compounds with transition metal ions such as copper. It was shown that up to 2–4 peptide molecules are associated around one charged metal center. A hypothesis on the mechanism of formation of these clusters is proposed in this work, which is confirmed by experimental data.