Isolation of the nonprotein nitrogen fraction from human milk by gel-filtration chromatography and its separation by fast protein liquid chromatography

S. M. Donovan, B. Lonnerdal

Research output: Contribution to journalArticle

8 Scopus citations

Abstract

Human milk (HM) is unique compared with the milk of other species in that nonprotein nitrogen (NPN) constitutes 20-25% of the total N. the NPN fraction consists of a diverse group of compounds with molecular masses < 10 000 Da (in the picogram to microgram per milliliter range), which have only been partially characterized. We have developed a methodology to separate and concentrate the NPN fraction for further analysis. NPN was initially separated from other milk components by Sephadex® G-25 gel filtration. Further isolation and separation was carried out by fast protein liquid chromatography gel filtration and ion-exchange chromatography. Molecular masses of unknown peaks were determined by using known molecular mass markers and standards. The methodologies developed lead to the discrete separation of NPN from other milk compounds and can be particularly valuable for isolating peptides in HM.

Original languageEnglish (US)
Pages (from-to)53-57
Number of pages5
JournalAmerican Journal of Clinical Nutrition
Volume50
Issue number1
StatePublished - 1989

ASJC Scopus subject areas

  • Food Science
  • Medicine (miscellaneous)

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