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Evaluating the Extent of Protein Damage in Dairy Products
Author(s) -
Hegele Jörg,
Parisod Véronique,
Richoz Janique,
Förster Anke,
Maurer Sarah,
Krause René,
Henle Thomas,
Bütler Timo,
Delatour Thierry
Publication year - 2008
Publication title -
annals of the new york academy of sciences
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.712
H-Index - 248
eISSN - 1749-6632
pISSN - 0077-8923
DOI - 10.1196/annals.1433.016
Subject(s) - chemistry , isotope dilution , glycation , chromatography , electrospray ionization , mass spectrometry , tandem mass spectrometry , lysine , analyte , electrospray , selected reaction monitoring , hydrolysis , dilution , proteolysis , enzyme , biochemistry , amino acid , physics , receptor , thermodynamics
An isotope dilution liquid chromatography‐tandem mass spectrometry (LC‐MS/MS) method was developed to determine lysine (Lys), N ε ‐fructosyllysine (FL), N ε ‐carboxymethyllysine (CML), and pyrraline (Pyr) in dairy products. The presented approach entails protein cleavage via enzymatic digestion to liberate the aforementioned compounds, which were then quantified using a stable isotope dilution assay. LC‐MS/MS analysis was performed by positive electrospray ionization recording two transition reactions per analyte in selected reaction monitoring mode. The CML and Lys values obtained with enzymatic digestion were compared to those acquired with acid hydrolysis HCl (6 mol/L), and the two proteolysis methods yielded comparable quantifications. Allowing for the fact that the investigated compounds are formed during different stages of the glycation process, the method is able to reveal the progress of protein glycation in dairy products.