Chromatographic characterization of ovine kappa-casein macropeptide.
Ovine casein macropeptide (CMP) was characterized by anion-exchange FPLC and reversed-phase (RP) HPLC. To study heterogeneity (the degree of glycosylation and phosphorylation), CMP was desialylated with neuraminidase and dephosphorylated with acid phosphatase. Following RP-HPLC, the main CMP components were identified using either on-line or off-line mass spectrometry. The most abundant ovine CMP component was a diphosphorylated carbohydrate-free form, followed by one or two monophosphorylated and a non-phosphorylated asialo-aglyco species. Aglyco non-phosphorylated, monophosphorylated and diphosphorylated forms were in the ratio 3:20:77. Only approximately 30% of ovine CMP was glycosylated. Assuming that the monosaccharide fraction of ovine CMP is composed of N-acetylgalactosamine, galactose and N-glycolylneuraminic acid, molecular masses consistent with the presence of CMP containing tetra-, tri-, di- and monosaccharide were identified.
Moreno
F J
FJ
Instituto de Fermentaciones Industriales (CSIC), Madrid, España.
Recio
I
I
Olano
A
A
López-Fandiño
R
R
D000135:Acid Phosphatase / Q000378:metabolism; D000818:Animals; D050260:Carbohydrate Metabolism; D002364:Caseins / Q000737:chemistry* / Q000378:metabolism; D002417:Cattle; D002851:Chromatography, High Pressure Liquid; D002852:Chromatography, Ion Exchange; D005260:Female; D006031:Glycosylation; D013058:Mass Spectrometry; D008892:Milk / Q000737:chemistry*; D009439:Neuraminidase / Q000378:metabolism; D010455:Peptides / Q000378:metabolism*; D010766:Phosphorylation; D012756:Sheep / Q000502:physiology
D002364:Caseins; D010455:Peptides; D000135:Acid Phosphatase; D009439:Neuraminidase