alpha 1,3-Fucosylation of branched blood group I-type oligo-(N-acetyllactosamino)glycans by human milk transferases is restricted to distal N-acetyllactosamine units: the resulting isomers are separated by WGA-agarose chromatography.
A partially purified preparation of alpha 1,3-fucosyltransferase(s) from human milk was used to [14C]fucosylate oligosaccharides containing Gal beta 1-4GlcNAc units. Substitution of N-acetyllactosamine at position 3' with a beta-linked N-acetyl-glucosamine enhanced the reactivity of the acceptor, whereas similar substitution at position 6' was inhibitory. Thus, the trisaccharide GlcNAc beta 1-6Gal beta 1-4GlcNAc (5), the branched tetrasaccharide GlcNAc beta 1-3(GlcNAc beta 1-6)Gal beta 1-4GlcNAc (11) and the triply branched decasaccharide GlcNAc beta 1-3(GlcNAc beta 1-6)Gal beta 1-4GlcNAc beta 1-3[GlcNAc beta 1-3(GlcNAc beta 1-6)Gal beta 1-4GlcNAc beta 1-6]Gal beta 1-4GlcNAc (26) gave remarkably poor yields of alpha 1,3-fucosylated products in comparison to GlcNAc beta 1-3Gal beta 1-4GlcNAc (3). beta 1,4-Galactosyl derivatives of 5 and 11, however, gave good yields of alpha 1,3-fucosylated products, but the fucosylation was restricted to the distal N-acetyllactosamine units of Gal beta 1-4GlcNAc beta 1-6Gal beta 1-4GlcNAc (16), Gal beta 1-4GlcNAc beta 1-3(Gal beta 1-4GlcNAc beta 1-6)Gal beta 1-4GlcNAc (18) and also in Gal alpha 1-3Gal beta 1-4GlcNAc beta 1-3(Gal alpha 1-3Gal beta 1-4GlcNAc beta 1-6)Gal beta 1-4GlcNAc (22). Immobilized wheat germ agglutinin (WGA), possessing high affinity for 16 [1], revealed no affinity for the fucosylated derivative Gal beta 1-4(Fuc alpha 1-3)GlcNAc beta 1-6Gal beta 1-4GlcNAc (17). The isomeric heptasaccharides Gal beta 1-4(Fuc alpha 1-3)GlcNAc beta 1-3(Gal beta 1-4GlcNAc beta 1-6)Gal beta 1-4GlcNAc (19) and Gal beta 1-4GlcNAc beta 1-3[Gal beta 1-4(Fuc alpha 1-3)GlcNAc beta 1-6]Gal beta 1-4GlcNAc (20) were readily separated from each other on WGA agarose, and so were the isomeric nonasaccharides Gal alpha 1-3Gal beta 1-4(Fuc alpha 1-3)GlcNAc beta 1-3(Gal alpha 1-3Gal beta 1-4GlcNAc beta 1-6)Gal beta 1-4GlcNAc (23) and Gal alpha 1-3Gal beta 1-4GlcNAc beta 1-3[Gal alpha 1-3Gal beta 1-4(Fuc alpha 1-3)GlcNAc beta 1-6]Gal beta 1-4GlcNAc (24).
Niemelä
R
R
Institute of Biotechnology, University of Helsinki, Finland.
Natunen
J
J
Brotherus
E
E
Saarikangas
A
A
Renkonen
O
O
D000373:Agglutinins / Q000737:chemistry; D000606:Amino Sugars / Q000737:chemistry* / Q000378:metabolism*; D000818:Animals; D002240:Carbohydrate Sequence; D002847:Chromatography, Agarose / Q000379:methods; D005643:Fucose / Q000737:chemistry* / Q000378:metabolism*; D005647:Fucosyltransferases / Q000737:chemistry / Q000378:metabolism*; D005688:Galactosamine / Q000737:chemistry / Q000378:metabolism; D006801:Humans; D007048:I Blood-Group System / Q000737:chemistry; D007785:Lactose / Q000737:chemistry / Q000378:metabolism*; D007983:Lewis Blood Group Antigens / Q000737:chemistry; D008892:Milk / Q000201:enzymology*; D008969:Molecular Sequence Data; D009844:Oligosaccharides / Q000737:chemistry* / Q000378:metabolism*; D011134:Polysaccharides / Q000138:chemical synthesis / Q000145:classification / Q000378:metabolism*; D013329:Structure-Activity Relationship; D014908:Triticum / Q000737:chemistry
D000373:Agglutinins; D000606:Amino Sugars; D007048:I Blood-Group System; D007983:Lewis Blood Group Antigens; D009844:Oligosaccharides; D011134:Polysaccharides; D005643:Fucose; D005688:Galactosamine; D005647:Fucosyltransferases; D007785:Lactose