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Characterization of lactosylated proteins of infant formula powders using two‐dimensional gel electrophoresis and nanoelectrospray mass spectrometry
Author(s) -
Marvin Laure F.,
Parisod Véronique,
Fay Laurent B.,
Guy Philippe A.
Publication year - 2002
Publication title -
electrophoresis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.666
H-Index - 158
eISSN - 1522-2683
pISSN - 0173-0835
DOI - 10.1002/1522-2683(200208)23:15<2505::aid-elps2505>3.0.co;2-m
Subject(s) - chromatography , chemistry , mass spectrometry , electrospray ionization , protein mass spectrometry , tandem mass spectrometry , electrospray , bottom up proteomics , whey protein , two dimensional gel electrophoresis , trypsin , casein , gel electrophoresis , proteomics , enzyme , biochemistry , gene
Infant formula powders were analyzed by liquid chromatography‐electrospray ionization‐mass spectrometry (LC‐ESI‐MS) to assess the whey proteins quality, which may be altered by the heat treatment used during the processing conditions. Lactosylation was found to be the major chemical modification occurring in whey proteins. In parallel, a two‐dimensional (2‐D) gel electrophoresis was performed on the milk sample and the entire protein patterns were analyzed by nano‐ESI‐MS after cutting the different gel spots and in‐gel trypsin digestion. A highly selective and specific tandem MS technique has been developed to characterize and localize up to ten lactosylation sites in β‐lactoglobulin (β‐Lg) and α S2 ‐casein. α‐Lactalbumin (α‐La), with five lactosylated peptides, was found to be an interesting protein marker in the milk powder sample to detect chemical modification induced by the processing/storage conditions.