Reassessment of the acceptor specificity and general properties of the Lewis blood-group gene associated alpha-3/4-fucosyltransferase purified from human milk.
The acceptor specificity and general properties of a Lewis blood-group gene associated alpha-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 the O-4 position of N-acetylglucosamine in Type 1 (Gal beta 1-3GlcNAc-R) acceptors and the O-3 position of glucose in lactose-based (Gal beta 1-4Glc) oligosaccharides, and both used Type 1 sialylated compounds when the terminal N-acetylneuraminic acid was present in alpha-2,3 linkage. The striking difference between the two preparations was in their reactivity with Type 2 (Gal beta 1-4GlcNAc-R) chains; after Sephacryl S-200 chromatography the apparent KM values for the alpha-3/4- preparation with unsubstituted low-molecular-weight Type 2 oligosaccharides were considerably increased. Substitution of the terminal galactose with sialic acid in alpha-2,3 linkage decreased the KM values for low-molecular-weight oligosaccharides but no detectable incorporation of fucose was observed into N-acetyllactosamine end-groups of glycoproteins with N-linked oligosaccharide chains, irrespective of the presence of sialic acid in the terminal sequences.
Johnson
P H
PH
Division of Immunochemical Genetics, MRC Clinical Research Centre, Harrow, Middlesex, UK.
Donald
A S
AS
Feeney
J
J
Watkins
W M
WM
D002240:Carbohydrate Sequence; D002413:Cations, Divalent; D002853:Chromatography, Liquid; D005647:Fucosyltransferases / Q000737:chemistry / Q000235:genetics* / Q000302:isolation & purification; D005815:Genetic Code / Q000235:genetics*; D006026:Glycoside Hydrolases; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007983:Lewis Blood Group Antigens / Q000235:genetics*; D008745:Methylation; D008895:Milk, Human / Q000201:enzymology*; D008969:Molecular Sequence Data; D008970:Molecular Weight; D012680:Sensitivity and Specificity; D012685:Sepharose / Q000031:analogs & derivatives; D013379:Substrate Specificity
D002413:Cations, Divalent; D007983:Lewis Blood Group Antigens; C028326:concanavalin A-sepharose; D012685:Sepharose; D005647:Fucosyltransferases; C019818:3-galactosyl-N-acetylglucosaminide 4-alpha-L-fucosyltransferase; D006026:Glycoside Hydrolases