title: Two distinct UDP-galactose: 2-acetamido-2-deoxy-D-glucose 4 beta-galactosyltransferases in porcine trachea.
abstract: In previous studies on glycosyltransferase activities in porcine trachea, we demonstrated the presence of two galactosyltransferases which transfer galactose from UDP-galactose to N-acetylglucosamine (Sheares, B.T. and Carlson, D.M. (1983) J. Biol. Chem. 258, 9893-9898). One enzyme, UDP-galactose:N-acetylglucosamine 3 beta-galactosyltransferase, synthesized galactosyl-beta 1,3-N-acetylglucosamine while the other, UDP-galactose:N-acetylglucosamine 4 beta-galactosyltransferase, synthesized galactosyl-beta 1,4-N-acetylglucosamine. A third galactosyltransferase has now been demonstrated utilizing a solubilized membrane preparation from pig trachea, which also synthesizes galactosyl-beta 1,4-N-acetylglucosamine as determined by gas-liquid chromatography and Diplococcus pneumoniae beta-galactosidase treatment. This new UDP-galactose:N-acetylglucosamine 4 beta-galactosyltransferase is distinct from the lactose synthetase A protein in that it does not bind to alpha-lactalbumin-agarose or to N-acetylglucosamine-agarose. The enzyme is separable from the UDP-galactose:N-acetylgalactosaminyl-mucin 3 beta-galactosyltransferase by affinity chromatography on asialo ovine submaxillary mucin adsorbed to DEAE-Sephacel. This newly discovered 4 beta-galactosyltransferase binds to UDP-hexanolamine-Sepharose and is partially separated from UDP-galactose:N-acetylglucosamine 3 beta-galactosyltransferase by Sephacryl S-200 gel filtration chromatography. Neither high concentrations of N-acetylglucosamine (200 mM) nor alpha-lactalbumin inhibits the incorporation of galactose into galactosyl-beta 1,4-N-acetylglucosamine by this enzyme.
mesh_terms: D000818:Animals; D007527:Isoenzymes / Q000302:isolation & purification* / Q000378:metabolism; D007700:Kinetics; D007788:Lactose Synthase / Q000302:isolation & purification*; D009237:N-Acetyllactosamine Synthase / Q000302:isolation & purification* / Q000378:metabolism; D013379:Substrate Specificity; D013552:Swine; D014132:Trachea / Q000201:enzymology*; D001616:beta-Galactosidase / Q000378:metabolism
chemical_list: D007527:Isoenzymes; D007788:Lactose Synthase; D009237:N-Acetyllactosamine Synthase; D001616:beta-Galactosidase