ISSN:
1573-4986
Keywords:
A431 cells
;
α-3/4-fucosyltransferase
;
Lewis blood-group-gene encoded enzyme
;
Lea determinant
;
Leb determinant
;
X determinant
;
Y determinant
;
sialyl-Lea determinant
;
sialyl-X determinant
Source:
Springer Online Journal Archives 1860-2000
Topics:
Chemistry and Pharmacology
Notes:
Abstract A soluble α-3/4-fucosyltransferase secreted into the growth medium of the human A431 epidermoid carcinoma cell line has been purified 700 000 fold by a series of steps involving chromatography on Phenyl Sepharose 4B, CM-Sephadex C-50 and GDP-hexanolamine Sepharose 4B. The untreated spent culture medium transferred almost ten times more fucose to the subterminalN-acetylglicosamine residue in the Type 1 (Gal β1-3GlcNAc) disaccharide than to the subterminal sugar in the Type 2 (Gal β1-4GlcNAc) disaccharide; the relative activity with these two substrates remained virtually unchanged throughout the purification procedure. At no stage was any α-3-fucosyltransferase species acting solely onN-acetylglucosamine residues in Type 2 chains separated from the bulk of the α-3/4-fucosyltransferase activity. The purified enzyme preparation showed insignificant activity with glycoprotein substrates having N-linked oligosaccharide chains with terminal Type 2 sequences but transferred fucose to a mucin-type glycoprotein with O-linked oligosaccharide chains with terminal Type 1 structures. Lactose was a poor substrate but the activity of the enzyme was influenced by the presence of substituents on the terminal β-galactosyl residue and 2′-fucosyllactose was almost as good an acceptor as the Type 1 disaccharide. The properties of the purified enzyme with regard to specificity, divalent cation requirements, pH optimum, andM r, closely resembled those of the Lewis-blood-group gene associated α-3/4-fucosyltransferase isolated from human milk.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00737712
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