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Covalent interactions between amino acid side chains and oxidation products of caffeoylquinic acid (chlorogenic acid)
Author(s) -
Prigent Stéphanie VE,
Voragen Alfons GJ,
Li Feng,
Visser Antonie JWG,
van Koningsveld Gerrit A,
Gruppen Harry
Publication year - 2008
Publication title -
journal of the science of food and agriculture
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.782
H-Index - 142
eISSN - 1097-0010
pISSN - 0022-5142
DOI - 10.1002/jsfa.3275
Subject(s) - lysine , covalent bond , chemistry , tyrosine , histidine , tryptophan , side chain , cysteine , amino acid , dimer , monomer , serine , threonine , biochemistry , organic chemistry , phosphorylation , polymer , enzyme
BACKGROUND: Physicochemical properties and digestibility of proteins can be modified by covalent interactions with oxidized phenolic compounds, i.e., quinones. In order to control these interactions in food products, the covalent interactions between quinones from caffeoylquinic acid (CQA) and amino acid side chains were studied with mass spectrometry using N‐terminally protected amino acids. RESULTS: The addition of two molecules of CQA, presumably in the form of a pre‐formed dimer, was observed for lysine, tyrosine, histidine and tryptophan. A monomer of CQA seemed to be able to react with histidine and tryptophan, whereas no interaction with a CQA monomer was observed for lysine and tyrosine. Serine and threonine showed no covalent interactions with CQA. Cross‐linking between CQA and the side chains of two molecules of lysine is likely to occur also in proteins. The results show that protein cross‐linking may also be expected to occur via two tyrosine residues in the absence of other phenolic substrates. The side chains of lysine and tyrosine are more reactive than that of histidine and tryptophan. CONCLUSIONS: These results show that covalent protein modification by oxidized phenolics occurs preferentially via an initial dimerization and encompasses not only lysine and cysteine residues. Copyright © 2008 Society of Chemical Industry