Journal of Dairy Research

Table of Contents - 2000 - Volume 67, Issue 03  


Chromatographic characterization of ovine κ-casein macropeptide

F. JAVIER MORENO a1, ISIDRA RECIO a1, AGUSTÍN OLANO a1 and ROSINA LÓPEZ-FANDIÑO a1c1
a1 Instituto de Fermentaciones Industriales (CSIC), Juan de la Cierva 3, E-28006 Madrid, España

Abstract

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[ratio]20[ratio]77. Only [similar] 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.

(Received July 20 1999)
(Accepted February 7 2000)


Correspondence:
c1 For correspondence.