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Copper‐Aβ Peptides and Oxidation of Catecholic Substrates: Reactivity and Endogenous Peptide Damage
Author(s) -
Pirota Valentina,
Dell'Acqua Simone,
Monzani Enrico,
Nicolis Stefania,
Casella Luigi
Publication year - 2016
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.201603824
Subject(s) - peptide , reactivity (psychology) , endogeny , copper , chemistry , combinatorial chemistry , biochemistry , organic chemistry , medicine , pathology , alternative medicine
The oxidative reactivity of copper complexes with Aβ peptides 1–16 and 1–28 (Aβ16 and Aβ28) against dopamine and related catechols under physiological conditions has been investigated in parallel with the competitive oxidative modification undergone by the peptides. It was found that both Aβ16 and Aβ28 markedly increase the oxidative reactivity of copper(II) towards the catechol compounds, up to a molar ratio of about 4:1 of peptide/copper(II). Copper redox cycling during the catalytic activity induces the competitive modification of the peptide at selected amino acid residues. The main modifications consist of oxidation of His13/14 to 2‐oxohistidine and Phe19/20 to ortho ‐tyrosine, and the formation of a covalent His6‐catechol adduct. Competition by the endogenous peptide is rather efficient, as approximately one peptide molecule is oxidized every 10 molecules of 4‐methylcatechol.