title: Peptide stability in drug development. II. Effect of single amino acid substitution and glycosylation on peptide reactivity in human serum.
abstract: The determination of peptide stability in human serum (HS) or plasma constitutes a powerful screening assay for eliminating unstable peptides from further development. Herein we report on the stability in HS of several major histocompatibility complex (MHC)-binding peptides. Some of these peptides are in development for the novel treatment of selected autoimmune disorders such as rheumatoid arthritis and insulin-dependent diabetes. For most of the l-amino acid peptides studied, the predominant degradation mechanism is exopeptidase-catalyzed cleavage. Peptides that were protected by d-amino acids at both termini were found to be more stable than predicted, based on additivity of single substitutions. In addition, N-acetylglucosamine glycopeptides were significantly stabilized, even when the glycosylation site was several amino acids from the predominant site(s) of cleavage. This indicates that long-range stabilization is possible, and likely due to altered peptide conformation. Finally, the effect of single amino acid substitutions on peptide stability in HS was determined using a model set of poly-Ala peptides which were protected from exopeptidase cleavage, allowing the study of endopeptidase cleavage pathways.
authors.affiliation: Cytel Corporation, San Diego, California 92121.
authors.forename: M F
authors.initials: MF
authors.lastname: Powell
authors.forename: T
authors.initials: T
authors.lastname: Stewart
authors.forename: L
authors.initials: L
authors.lastname: Otvos
authors.forename: L
authors.initials: L
authors.lastname: Urge
authors.forename: F C
authors.initials: FC
authors.lastname: Gaeta
authors.forename: A
authors.initials: A
authors.lastname: Sette
authors.forename: T
authors.initials: T
authors.lastname: Arrhenius
authors.forename: D
authors.initials: D
authors.lastname: Thomson
authors.forename: K
authors.initials: K
authors.lastname: Soda
authors.forename: S M
authors.initials: SM
authors.lastname: Colon
mesh_terms: D000117:Acetylglucosamine / Q000737:chemistry; D000595:Amino Acid Sequence; D000596:Amino Acids / Q000097:blood / Q000737:chemistry*; D055598:Chemical Phenomena; D002627:Chemistry, Physical; D002851:Chromatography, High Pressure Liquid; D010450:Endopeptidases / Q000378:metabolism; D006027:Glycosides / Q000097:blood / Q000737:chemistry*; D006801:Humans; D006868:Hydrolysis; D007700:Kinetics; D008285:Major Histocompatibility Complex / Q000502:physiology; D008969:Molecular Sequence Data; D010447:Peptide Hydrolases / Q000378:metabolism; D010455:Peptides / Q000097:blood / Q000737:chemistry*
chemical_list: D000596:Amino Acids; D006027:Glycosides; D010455:Peptides; D010450:Endopeptidases; D010447:Peptide Hydrolases; D000117:Acetylglucosamine