title: 4-O-beta-D-galactopyranosyl-D-xylose: a new synthesis and application to the evaluation of intestinal lactase.
abstract: 4-O-beta-D-Galactopyranosyl-D-xylose (2) was prepared from benzyl 2,3-O-isopropylidene-beta-D-xylopyranoside by glycosylation with 2,3,4,6-tetra-O-benzoyl-alpha-D-galactopyranosyl bromide and subsequent deprotection. Compound 2 was hydrolyzed in vitro by intestinal lactase; the Vmax was 25% of that with lactose and the Km was 370mM (cf. 27mM for lactose). Oral administration of 2 suckling rats led to urinary excretion of D-xylose which could be estimated colorimetrically.
authors.affiliation: Grupo de Carbohidratos, Instituto de Química Orgánica, C.S.I.C., Madrid, Spain.
authors.forename: A
authors.initials: A
authors.lastname: Rivera-Sagredo
authors.forename: A
authors.initials: A
authors.lastname: Fernández-Mayoralas
authors.forename: J
authors.initials: J
authors.lastname: Jiménez-Barbero
authors.forename: M
authors.initials: M
authors.lastname: Martín-Lomas
authors.forename: D
authors.initials: D
authors.lastname: Villanueva
authors.forename: J J
authors.initials: JJ
authors.lastname: Aragón
mesh_terms: D000284:Administration, Oral; D000375:Aging; D000818:Animals; D000833:Animals, Suckling; D002240:Carbohydrate Sequence; D004187:Disaccharides / Q000138:chemical synthesis / Q000378:metabolism*; D007422:Intestines / Q000201:enzymology*; D043322:Lactase; D007785:Lactose / Q000378:metabolism; D008969:Molecular Sequence Data; D012756:Sheep; D014994:Xylose / Q000652:urine; D001616:beta-Galactosidase / Q000378:metabolism*
chemical_list: D004187:Disaccharides; C073827:4-O-galactopyranosylxylose; D014994:Xylose; D043322:Lactase; D001616:beta-Galactosidase; D007785:Lactose