title: Formation of a cyclic imide in aspartyl or asparaginyl glycyl peptides induced by heating in the dry state.
abstract: A common product was identified by HPLC from the heating of, alpha and beta isomers of, aspartyl glycine in the dry state. Fast atom-bombardment (FAB) mass spectrometry and Fourier transform infrared photoacoustic spectroscopy (FTIR-PAS) showed that the product is a cyclic imide. Cyclic imide formation also was shown to occur with the tripeptides Gly-Asp-Gly and Gly-Asn-Gly. The cyclization of aspartyl peptides depends upon protonation of the beta-carboxyl group and can be promoted by acidification or by heating the NH4+ salt in the dry state.
mesh_terms: D001216:Asparagine; D001224:Aspartic Acid; D002851:Chromatography, High Pressure Liquid; D004590:Electrophoresis, Paper; D006358:Hot Temperature; D007094:Imides; D007202:Indicators and Reagents; D013058:Mass Spectrometry; D009842:Oligopeptides / Q000138:chemical synthesis*; D010456:Peptides, Cyclic / Q000138:chemical synthesis*; D013053:Spectrophotometry
chemical_list: D007094:Imides; D007202:Indicators and Reagents; D009842:Oligopeptides; D010456:Peptides, Cyclic; C053567:glycyl-aspartyl-glycine; D001224:Aspartic Acid; C053566:glycyl-asparaginyl-glycine; D001216:Asparagine