1. Nonenzymatic Lactosylation of Bovine β-Lactoglobulin under Mild Heat Treatment Leads to Structural Heterogeneity of the Glycoforms
- Author
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Daniel Mollé, Joëlle Léonil, François Morgan, and Saïd Bouhallab
- Subjects
Whey protein ,Glycosylation ,Hot Temperature ,Electrospray ionization ,Molecular Sequence Data ,Lysine ,Biophysics ,Lactose ,Lactoglobulins ,Mass spectrometry ,Peptide Mapping ,Biochemistry ,Mass Spectrometry ,chemistry.chemical_compound ,Animals ,Amino Acid Sequence ,Amines ,Binding site ,Molecular Biology ,Beta-lactoglobulin ,Chromatography ,biology ,Cell Biology ,chemistry ,biology.protein ,Cattle - Abstract
Lactose reacts nonenzymatically with beta-lactoglobulin (beta-LG), the major whey protein, under mild heat treatment and the formation of the complex may be monitored by mass spectrometry. Using Reverse Phase HPLC coupled with Electrospray Ionization MS (ESI-MS) we have measured the global extent of glycosylation and examined the distribution of lactose among the beta-LG glycoforms. Identification of lactosylated sites by trypsinolysis and Tandem MS indicate that, although the glycosylation reaction was non-specific and potentially involved all the reactive sites (alpha- and epsilon-amino groups), beta-LG appeared to have at least two populations of lysine with the distinct ability to react with lactose. These results underline the structural heterogeneity of beta-LG glycoforms, with respect to the number of lactose linked per molecule and to the binding sites involved, which could affect the biological function of beta-LG.
- Published
- 1997