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Reactions of Hydrogen Atoms with Met‐Enkephalin and Related Peptides
Author(s) -
Mozziconacci Olivier,
Bobrowski Krzysztof,
Ferreri Carla,
Chatgilialoglu Chryssostomos
Publication year - 2007
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.200600828
Subject(s) - chemistry , radiolysis , vesicle , isomerization , liposome , radical , peptide , enkephalin , phosphatidylcholine , hydrogen atom , pentapeptide repeat , residue (chemistry) , stereochemistry , catalysis , biochemistry , phospholipid , alkyl , organic chemistry , receptor , membrane , opioid
The reactions of hydrogen atoms with enkephalins and related peptides have been investigated by radiolytic methods in aqueous solutions and lipid vesicle suspensions. Pulse radiolysis experiments indicate that methionine residue (Met) is the main target. In Met‐enkephalin (Tyr‐Gly‐Gly‐Phe‐Met) the attack of the hydrogen atom occurs to about 50 % on Met with formation of methanethiyl radical. The remaining percentage is divided roughly evenly between Tyr and Phe. With Leu‐enkephalin (Tyr‐Gly‐Gly‐Phe‐Leu) the site of attack is limited to Tyr and Phe. Using a peptide–liposome (that is, 1‐palmitoyl‐2‐oleoyl phosphatidylcholine vesicles) model, the cis – trans isomerization of phospholipids could be detected due to the catalytic action of thiyl radicals. The radiation chemical yields of the H . and, consequently of CH 3 S . radical, was modulated by the experimental conditions and the nature of peptide. Large amounts of trans lipids observed in phosphate buffer vesicle suspensions indicated the efficient role of double‐bond isomerization as marker of Met‐containing peptide damage.