Identification of a β-lactoglobulin lactosylation site

Vincenzo Fogliano*, Simona M. Monti, Attilio Visconti, Giacomino Randazzo, Angelo M. Facchiano, Giovanni Colonna, Alberto Ritieni

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

80 Citations (Scopus)

Abstract

Thermal treatment of milk leads to non-enzymatic glycosylation of proteins through Maillard reaction. Free NH2 groups of basic amino acids react with the reducing carbonyl group of lactose forming the so-called Amadori products. Electrospray mass spectrometry analysis shows that β-lactoglobulin (β-LG), the major whey protein, undergoes lactosylation under industrial thermal treatment. In order to investigate the specificity of reactive sites for lactose binding the analysis of trypsin hydrolysates of β-LG isolated from different industrial milks was performed. Results demonstrate that Lys-100 is a preferential lactosylation site of β-LG during industrial milk treatment. These results were confirmed by an analysis of the three-dimensional model of the protein which showed that Lys-100 had the highest solvent accessibility and proximity to another amino group making Lys-100 the best candidate to lactosylation. Lys-47, previously identified by other authors, showed a good proximity to another Lys residue, but an intermediate level of exposition to solvent. Copyright (C) 1998 Elsevier Science B.V.

Original languageEnglish
Pages (from-to)295-304
Number of pages10
JournalBiochimica et Biophysica Acta - Protein Structure and Molecular Enzymology
Volume1388
Issue number2
DOIs
Publication statusPublished - 10 Nov 1998
Externally publishedYes

Keywords

  • β-Lactoglobulin
  • Amadori compound
  • Glycosylation
  • Lactosylation
  • Liquid chromatography-mass spectrometry
  • Maillard reaction
  • Milk
  • Thermal treatment

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