AUTHOR=Bikaki Maria , Kuhnert Nikolai TITLE=“Thermal Peroxidation” of Dietary Pentapeptides Yields N-Terminal 1,2-Dicarbonyls JOURNAL=Frontiers in Nutrition VOLUME=8 YEAR=2021 URL=https://www.frontiersin.org/journals/nutrition/articles/10.3389/fnut.2021.663233 DOI=10.3389/fnut.2021.663233 ISSN=2296-861X ABSTRACT=

In this contribution we investigate the thermal degradation of dietary-relevant pentapeptides. Most unsaturated lipids degrade by the well-known peroxidation mechanism. Here we show a degradation mechanism of peptides analogous to lipid peroxidation, forming a series of novel degradation products with possible toxicological relevance. At elevated temperatures above 180°C, pentapeptides with an N-terminal phenylalanine moiety react via a debenzylation to form 1,2-dicabonyl compounds, replacing the N-terminal primary amine. We propose a radical-based reaction mechanism that leads via a common peroxoaminal intermediate to two distinct types of reaction products with a terminal α-1,2 diamide or an α-amide-aldehyde functionality.