title: On-line electrogeneration of copper-peptide complexes in microspray mass spectrometry.
abstract: The interaction of copper ions with peptides was investigated by electrospray mass spectrometry. Two electrospray micro-emitters were compared, the first one with a platinum electrode using a copper(II) electrolyte solution containing a peptide sample, and the second one with a sacrificial copper anode in a water/methanol solution containing only a peptide (i.e., angiotensin III, bradykinin, or Leu-enkephalin). The former yielded mainly Cu(2+) complexes either with histidine residues or with the peptide backbone (Cu(+) complexes can be also formed due to gas-phase reactions), whereas the latter can generate a mixture of both Cu(+) and Cu(2+) aqueous complexes that yield different complexation patterns. This study shows that electrospray emitters with soluble copper anodes enable the study of Cu(I)-peptide complexes in solution.
authors.affiliation: Laboratoire d'Electrochimie Physique et Analytique, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland.
authors.forename: Michel
authors.initials: M
authors.lastname: Prudent
authors.forename: Hubert H
authors.initials: HH
authors.lastname: Girault
mesh_terms: D000809:Angiotensins / Q000737:chemistry; D001920:Bradykinin / Q000737:chemistry; D003300:Copper / Q000737:chemistry*; D004743:Enkephalin, Leucine / Q000737:chemistry; D006801:Humans; D008832:Microchemistry; D010455:Peptides / Q000737:chemistry*; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*
chemical_list: D000809:Angiotensins; D010455:Peptides; C042514:cuprous ion; D004743:Enkephalin, Leucine; D003300:Copper; D001920:Bradykinin