title: Alkylation of tryptophan during deprotection of Tmob-protected carboxamide side chains.
abstract: Alkylation of tryptophan occurred during the synthesis of a 19-amino acid peptide of the following sequence: Tyr Ala Ala Gln Asn Arg Arg Gly Leu Asp Leu Leu Phe Trp Glu Gln Gly Gly Leu. Alkylation was found to occur during cleavage of the peptide from the solid support under acidic conditions in the presence of Tmob, which is used for protecting glutamine and asparagine. Presence of alkylated tryptophan was confirmed by mass spectrometry, HPLC and amino acid sequence analyses.
authors.affiliation: Abbott Laboratories, Abbott Park, IL 60064.
authors.forename: D
authors.initials: D
authors.lastname: Shah
authors.forename: A
authors.initials: A
authors.lastname: Schneider
authors.forename: S
authors.initials: S
authors.lastname: Babler
authors.forename: R
authors.initials: R
authors.lastname: Gandhi
authors.forename: E
authors.initials: E
authors.lastname: Van Noord
authors.forename: E
authors.initials: E
authors.lastname: Chess
mesh_terms: D000478:Alkylation; D000595:Amino Acid Sequence; D000596:Amino Acids / Q000737:chemistry*; D001593:Benzyl Compounds / Q000737:chemistry*; D008969:Molecular Sequence Data; D014364:Tryptophan / Q000737:chemistry*
chemical_list: D000596:Amino Acids; D001593:Benzyl Compounds; D014364:Tryptophan