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Human alpha s1-casein: purification and characterization.

L K Rasmussen·H A Due·T E Petersen
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Abstract

The human counterpart of alpha s1-casein has been purified by a combination of gel-filtration and ion-exchange chromatography under denaturing conditions. SDS-PAGE analysis revealed the presence of a diffuse ladder with a high molecular mass which upon reduction was replaced by several closely spaced bands of lower molecular masses and a broad diffuse band corresponding to kappa-casein. Amino acid sequence analysis of the closely spaced bands all resulted in the same N-terminal sequence which was found to be homologous with alpha s1-casein from other species. Sequence analysis of a major radiolabelled tryptic peptide from purified 14C-carboxymethylated alpha s1-casein demonstrated that the protein contains at least two cysteine residues. As judged by SDS-PAGE in the presence or absence of a reducing agent, the molecular structure of the polymers constituting the ladder is composed of heteropolymers of alpha s1- and kappa-casein cross-linked by disulfide bonds.

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Amino Acid SequenceAnimalsCaseinsChromatography, GelChromatography, Ion ExchangeDisulfidesElectrophoresis, Polyacrylamide GelHumansMacromolecular SubstancesMilk, HumanMolecular Sequence DataMolecular WeightPeptide FragmentsSequence AnalysisSequence HomologyTrypsinComparative StudyJournal ArticleResearch Support, Non-U.S. Gov't

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L K Rasmussen, H A Due, T E Petersen. 1995. Human alpha s1-casein: purification and characterization.. https://doi.org/10.1016/0305-0491(94)00225-j

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