9-Oxononanoic Acid and Its Lysine Schiff Base Adduct as a Novel Lipation Product in Peanuts
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Contributors
Abstract
9-Oxononanoic acid (9-ONA) was quantitated in peanuts roasted at 170 °C by GC-MS (EI). After roasting peanuts for 40 min, 9-ONA decreased from 1010 μmol/kg protein in the unheated sample to 722 μmol/kg protein, most likely due to modifications of nucleophilic side chains of protein-bound amino acids (lipation). After heating Nα-acetyl-l-lysine and 9-ONA in model experiments, a Schiff base in its reduced form, namely, Nϵ-carboxyoctyl-acetyl lysine, as well as two isomeric pyridinium derivatives, namely, dicarboxyhexylcarboxyheptylpyridinium-acetyl lysine 1 and 2, were tentatively identified by HPLC-ESI-MS/MS. Based on the identified lipation products of 9-ONA, it can be assumed that lipation reactions represent a mirror-image reaction. For quantitation of Nϵ-carboxyoctyllysine (COL) in roasted peanuts by means of HPLC-ESI-MS/MS, samples were reduced with sodium borohydride and acid hydrolyzed. For the first time, COL was quantitated after reduction in roasted peanuts. Furthermore, after prolonged roasting of peanuts for 40 min, COL decreased from 139.8 to 22.5 μmol/kg protein, which provides initial evidence for lipation of nucleophilic side chains of protein-bound amino acids by glycerol-bound oxidized fatty acids (GOFAs, e.g., 9-ONA) with the formation of neo-lipoproteins.
Details
Original language | English |
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Pages (from-to) | 7820-7828 |
Number of pages | 9 |
Journal | Journal of agricultural and food chemistry |
Volume | 71 |
Issue number | 20 |
Publication status | Published - 24 May 2023 |
Peer-reviewed | Yes |
External IDs
PubMed | 37172279 |
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Keywords
ASJC Scopus subject areas
Keywords
- 9-oxononanoic acid, COL, glycerol-bound oxidized fatty acids, lipation, lipid peroxidation, mirror-image reaction, N-carboxyoctyllysine, neo-lipoproteins, peanut