Critical Examination of a Method for the Analysis of α and ω Linkages in Peptides Containing Aspartic Acid and Glutamic Acid

Article abstract of DOI:10.1021/jo00160a015

Coupling of O-pivaloylhydroxylamine (4) and subsequent Lossen rearrangement under mild conditions led to the disappearence of β-aspartyl and γ-glutamyl residues from subsequent amino acid analysis in a variety of peptides.Residues from the usual α linkage rearrange much more sluggishly to products that are detectable by amino acid analysis.An interesting complication in the procedure is that α-linked glutamyl residues are converted in part to a 2-oxohexahydropyrimidine-4-carboxylic acid derivative which is stable to extended acid hydrolysis.After base hydrolysis this deri vative yields 2,4-diaminobutanoic acid.This reaction explains aberrant results in the linkage analysis of collagen that have been reported in the literature.