Human-milk proteins: Analysis of casein and casein subunits by anion-exchange chromatography, gel electrophoresis, and specific staining methods

Clemens Kunz, Bo Lönnerdal

Research output: Contribution to journalArticle

84 Scopus citations

Abstract

Casein in human milk is believed to serve several biological functions in newborns. However, the content and subunit composition of human casein has so far received little attention. We recently developed a method to separate human-milk whey and casein by adjustment of whole human milk to pH 4.3 and addition of calcium followed by ultracentrifugation. In this study we analyzed and evaluated human casein prepared by different methods. We used fast protein liquid chromatography (FPLC) with an anion-exchange column (Mono-Q) and polyacrylamide gradient gel electrophoresis techniques to analyze the casein subunit composition. Total casein in human milk, as determined by the Kjeldahl method, varies during lactation; the casein content is ∼20% of the total protein content in early lactation and 45% in late lactation. We found differences in both glycosylation and phosphorylation patterns of κ-caseins and β-caseins from premature and term milk samples.

Original languageEnglish (US)
Pages (from-to)37-46
Number of pages10
JournalAmerican Journal of Clinical Nutrition
Volume51
Issue number1
StatePublished - Jan 1990

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Keywords

  • β-casein
  • κ-casein
  • Casein
  • Casein subunits
  • FPLC anion-exchange chromatography
  • Gel electrophoresis
  • Human-milk proteins

ASJC Scopus subject areas

  • Medicine (miscellaneous)
  • Food Science

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