Enantiomer discrimination of peptides by tandem mass spectrometry: influence of the peptide sequence on chiral recognition.
The enantiomer discrimination of peptides by electrospray ionization tandem mass spectrometry is described. A cinchona alkaloid derivative, tert-butylcarbamoylquinine, is used as chiral selector. The chiral selector forms diastereomeric complexes with the peptide enantiomers in the liquid phase (methanolic solution), which are then transferred to the gas phase, where their dissociation behaviour is studied in an ion-trap mass spectrometer. Different degrees of dissociation of the diastereomeric complexes allow for the discrimination of the peptide enantiomers. The influence of the peptide sequence on enantiomer discrimination is discussed and molecular recognition information is derived by comparing the results obtained for related peptides. For dipeptides, small amino acid residues at the N-terminus and bulky side chains at the C-terminus were found to enhance chiral recognition, while for tripeptides the effects were rather irregular.
Czerwenka
Christoph
C
Institute of Analytical Chemistry, University of Vienna, Währingerstrasse 38, 1090 Wien, Austria.
Lindner
Wolfgang
W
D000595:Amino Acid Sequence; D002219:Carbamates / Q000737:chemistry; D002930:Cinchona Alkaloids / Q000737:chemistry; D010455:Peptides / Q000032:analysis*; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*; D013237:Stereoisomerism
D002219:Carbamates; D002930:Cinchona Alkaloids; D010455:Peptides