Variations and distributions of O-glycosidically linked sugar chains in bovine kappa-casein.
The variation and distribution of O-glycosidically linked sugar chains in kappa-casein from bovine mature milk were analyzed by HPLC, fast atom bombardment mass spectrometry, and 13C nuclear magnetic resonance. A monosaccharide alditol (N-acetylgalactosaminitol) and four oligosaccharide alditols [a neutral disaccharide (galactosyl-beta 1-3N-acetylgalactosaminitol), two acidic trisaccharides (straight chain: N-acetylneuraminyl alpha 2-3galactosyl-beta 1-3N-acetylgalactosaminitol and branch chain: galactosyl beta 1-3(N-acetylneuraminyl alpha 2-6)N-acetylgalactosaminitol), and an acidic tetrasaccharide(N-acetylneuraminyl alpha 2-3galactosyl-beta 1-3(N-acetylgalactosaminyl alpha 2-6)N-acetylgalactosaminitol] were identified as sugar chains linking on normal bovine kappa-casein. The most dominant sugar chain was an acidic tetrasaccharide. The four oligosaccharide chains were identical to those already found, but N-acetylgalactosamine was a newly identified sugar chain linking on kappa-casein. The distribution of monosaccharide, disaccharide, trisaccharide (straight), trisaccharide (branched), and tetrasaccharide chains were determined by HPLC to be .8, 6.3, 18.4, 18.5, and 56.0%, respectively (means of five kappa-caseins).
Saito
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Laboratory of Animal Products Chemistry, College of Agriculture, Tohoku University, Miyagi, Japan.
Itoh
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D000818:Animals; D002240:Carbohydrate Sequence; D002364:Caseins / Q000737:chemistry*; D002417:Cattle; D002851:Chromatography, High Pressure Liquid; D005260:Female; D009682:Magnetic Resonance Spectroscopy; D008969:Molecular Sequence Data; D016339:Spectrometry, Mass, Fast Atom Bombardment
D002364:Caseins