title: Selective separations of peptides with sequence deletions, single amino acid polymorphisms, and/or epimeric centers using macrocyclic glycopeptide liquid chromatography stationary phases.
abstract: Separating closely related peptides (those differing by one or two amino acids or the chirality of a single amino acid) can be challenging using reversed-phase liquid chromatography (LC), ion-exchange LC, or using ion-pairing agents. Also, the mobile phases that give the best separations in these modes may not be electrospray ionization mass spectrometry (ESI-MS) compatible. Forty-two peptides from 11 peptide families were separated on three macrocyclic glycopeptide stationary phases in reverse-phase mode using ESI-MS-compatible mobile phases. The peptide classes studied were angiotensin, bradykinin, alpha-bag cell factor, beta,gamma-bag cell factor, beta-casomorphin, dynorphin, enkephalin, leucokinin, lutinizing hormone releasing hormone, neurotinsin, substance P, and vasopressin. High selectivity was observed for single amino acid substitutions (achiral and chiral) regardless of the position of the substitution in the sequence. Mobile phase optimization, its effect on peptide elution behavior, and chromatographic efficiency is also discussed. Using LC-ESI-MS, a 2 ng limit of detection was obtained, two orders of magnitude lower than the UV detection limit.
authors.affiliation: Department of Chemistry, Iowa State University, Ames, IA 50011-3111, USA.
authors.forename: Bo
authors.initials: B
authors.lastname: Zhang
authors.forename: Renee
authors.initials: R
authors.lastname: Soukup
authors.forename: Daniel W
authors.initials: DW
authors.lastname: Armstrong
mesh_terms: D000595:Amino Acid Sequence; D000596:Amino Acids / Q000737:chemistry / Q000235:genetics*; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D006020:Glycopeptides / Q000737:chemistry*; D008969:Molecular Sequence Data; D010455:Peptides / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification*; D011110:Polymorphism, Genetic; D021241:Spectrometry, Mass, Electrospray Ionization; D013056:Spectrophotometry, Ultraviolet
chemical_list: D000596:Amino Acids; D006020:Glycopeptides; D010455:Peptides