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  • 1
    ISSN: 1573-4986
    Keywords: α-3/4-L-Fucosyltransferase ; α-3-L-fucosyltransferase ; Lewis-gene encoded enzyme ; Lewis antigens ; X-antigen ; human milk
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract A soluble Lewis blood-group gene associated α-3/4-L-fucosyltransferase has been purified from human milk by a series of steps involving hydrophobic chromatography on Phenyl Sepharose 4B, ion exchange chromatography on CM-Sephadex C-50, affinity chromatography on GDP-hexanolamine Sepharose 4B and gel filtration on Sephacryl S-200. The first step separated α-3-L-fucosyltransferase activity directed towardsN-acetylglucosamine in Type 2 (Galβ1-4GlcNAc-R) acceptors from an α-3/4-fucosyltransferase fraction acting on both Type 1 (Galβ1-3GlcNAc-R) and Type 2 acceptors. Further purification of this latter fraction on CM-Sephadex and GDP-hexanolamine Sepharose gave a single peak of fucosyltransferase activity that catalysed the addition of fucose toN-acetylglucosamine in both Type 1 and Type 2 acceptors and to theO-3 position of glucose in lactose-based oligosaccharides. The enzyme preparation at this stage resembled previously described α-3/4-fucosyltransferase preparations purified from human milk. However, gel filtration of this preparation on Sephacryl S-200 or Sephadex G-150 separated further amounts of α-3-fucosyltransferase activity acting solely on Type 2 acceptors and left a residual α-3/4-fucosyltransferase that retained strong α-4 activity with the Type 1 acceptor, lacto-N-biose 1, and α-3 activity with 2′-fucosyllactose, but had relatively little α-3 activity withN-acetyllactosamine and virtually no capacity to transfer fucose to glycoproteins withN-linked oligosaccharide chains having unsubstituted terminal Type 2 structures.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1573-4986
    Keywords: α-3/4-L-fucosyltransferase ; Lewis blood-group gene encoded enzyme ; Lewis antigens ; sialyl-Lea ; X-antigen ; sialyl-X antigen ; human milk
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The acceptor specificity and general properties of a Lewis blood-group gene associated α-3/4-L-fucosyltransferase isolated from human milk have been examined at the penultimate purification stage involving affinity chromatography on GDP-hexanolamine Sepharose, and after a subsequent gel filtration step on Sephacryl S-200. Both preparations transferred fucose to theO-4 position ofN-acetylglucosamine in Type 1 (Galβ1-3GlcNAc-R) acceptors and theO-3 position of glucose in lactose-based (Galβ1-4Glc) oligosaccharides, and both used Type 1 sialylated compounds when the terminalN-acetylneuraminic acid was present in α-2,3 linkage. The striking difference between the two preparations was in their reactivity with Type 2 (Galβ1-4GlcNAc-R) chains; after Sephacryl S-200 chromatography the apparentK M values for the α-3/4- preparation with unsubstituted low-molecular-weight Type 2 oligosaccharides were considerably increased. Substitution of the terminal galactose with sialic acid in α-2,3 linkage decreased theK M values for low-molecular-weight oligosaccharides but no detectable incorporation of fucose was observed intoN-acetyllactosamine end-groups of glycoproteins withN-linked oligosaccharide chains, irrespective of the presence of sialic acid in the terminal sequences.
    Type of Medium: Electronic Resource
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