title: Glycosyltransferases of the human cervical epithelium. I. Characterization of a beta-galactoside alpha-2-L-fucosyltransferase and the identification of a beta-N-acetylglucosaminide alpha-3-L-fucosyltransferase.
abstract: Using phenyl beta-D-galactoside as an acceptor, alpha-2-L-fucosyltransferase activity was identified in human cervical epithelium with pH optima at 6.0 and 7.2. The different response to p-chloromercuribenzoate, and ability to utilise asialofetuin as an acceptor, suggests the presence of two fucosyltransferases. The acid form is probably involved in glycoprotein synthesis in vivo. At pH 6.0, fucosyltransferase has a temperature optimum of 25 degrees C, requires the presence of Triton X-100 and either manganese or magnesium for maximal activity, and has Km values for GDP-L-[14-C]fucose and phenyl beta-D-galactoside of 32.1 . 10(-6) M and 8.2 . 10(-3) M, respectively. Guanosine nucleotides are potent inhibitors of the fucosyltransferase reaction; GDP is a competitive inhibitor while, depending on its concentration, GTP can either inhibit or activate the reaction. The alpha-L-fucosidase present in cervical tissue has negligible activity towards the enzyme product, phenyl-alpha-2-L-[14C]fucosyl-beta-D-galactoside. The use of high and low molecular weight acceptors indicates the presence of a beta-N-acetylglucosaminide alpha-3-L-fucosyltransferase and an N-acetylgalactosaminide fucosyltransferase.
mesh_terms: D001212:Asialoglycoproteins; D002584:Cervix Uteri / Q000201:enzymology*; D002729:Chloromercuribenzoates / Q000494:pharmacology; D004355:Drug Stability; D004789:Enzyme Activation; D004848:Epithelium / Q000201:enzymology*; D005260:Female; D060748:Fetuins; D005647:Fucosyltransferases / Q000032:analysis* / Q000378:metabolism*; D005697:Galactosides / Q000378:metabolism; D006150:Guanine Nucleotides / Q000494:pharmacology; D006154:Guanosine Diphosphate Fucose / Q000378:metabolism; D006602:Hexosyltransferases / Q000032:analysis* / Q000378:metabolism*; D006801:Humans; D000509:alpha-Fetoproteins / Q000378:metabolism; D020245:p-Chloromercuribenzoic Acid; D000097631:Galactoside 2-alpha-L-fucosyltransferase
chemical_list: D001212:Asialoglycoproteins; D002729:Chloromercuribenzoates; D060748:Fetuins; D005647:Fucosyltransferases; D005697:Galactosides; D006150:Guanine Nucleotides; D006154:Guanosine Diphosphate Fucose; D006602:Hexosyltransferases; D000509:alpha-Fetoproteins; D020245:p-Chloromercuribenzoic Acid; D000097631:Galactoside 2-alpha-L-fucosyltransferase; C017029:asialofetuin; C031680:phenyl-alpha-2-fucosyl-beta-D-galactoside; C031692:galactoside 3-fucosyltransferase