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Modification of lysine amino groups by the lipid peroxidation product 4,5( E )‐Epoxy‐2( E )‐hepteal
Author(s) -
Zamora Rosario,
Hidalgo Francisco J.
Publication year - 1994
Publication title -
lipids
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.601
H-Index - 120
eISSN - 1558-9307
pISSN - 0024-4201
DOI - 10.1007/bf02536328
Subject(s) - chemistry , pyrrole , chromatography , derivatization , substituent , lysine , high performance liquid chromatography , diastereomer , amino acid , organic chemistry , biochemistry
The reaction between 4,5( E )‐epoxy‐2( E )‐heptenal (EH) and l ‐lysine was studied to characterize some of the compounds that may be produced when proteins react with peroxidizing lipids. A mixture of EH and lysine was incubated overnight at room temperature and then fractionated by high‐performance liquid chromatography (HPLC). Fractions were freeze‐dried and characterized by 1 H and 13 C nuclear magnetic resonance (NMR) and mass spectrometry. Four major pyrrole derivatives were obtained, namely 1‐(5′‐amino‐1′‐carboxypentyl)‐pyrrole (3), 1‐(5′‐amino‐1′‐carboxypentyl)‐2‐(1″‐hydroxypropyl)pyrrole (diastereomers 5 and 8), 1‐(5′‐amino‐5′‐carboxypentyl)pyrrole (7), and 1‐(5′‐amino‐5′‐carboxypentyl)‐2‐(1″‐hydroxypropyl)pyrrole (9). In addition, several lysine complexes were detected. A polymer (1b) that was responsible for the color and the fluorescence produced in the reaction was isolated by gel filtration chromatography from a fraction obtained by HPLC. Formation of pairs of analogs (5 and 3, 9 and 7) with and without a substituent in position 2 of the pyrrole ring suggested that the compounds were produced by the same mechanism, with the formation of the 2‐unsubstituted pyrroles corresponding to the loss of the 2‐substituent as propanal; propanal was detected by headspace capillary gas chromatography. A reaction mechanism is proposed based on the NMR data obtained when the reaction was monitored in real time in an NMR tube. The results suggest that pyrrolic amino acids 7 and 9 may be present in proteins that have been damaged by peroxidizing lipids.