A direct enzymatic synthesis of β- d-galactopyranosyl- d-xylopyranosides and their use to evaluate rat intestinal lactase activity in vivo

• Published in: Carbohydrate research 1996-09, Vol.290 (2), p.209-216
• Main Authors: Aragón, Juan J., Cañada, Francisco J., Fernández-Mayoralas, Alfonso, López, Rosa, Martín-Lomas, Manuel, Villanueva, Daniel
• Format: Article
• Language: English
• Subjects: Acetylation; Animals; beta-Galactosidase - metabolism; Carbohydrate Conformation; Chromatography, Gas; Disaccharides - chemical synthesis; Disaccharides - metabolism; E. coli β- d-galactosidase; Enzymatic glycosylation; Escherichia coli - enzymology; Galactose - analogs & derivatives; Glycosides - chemical synthesis; Intestinal lactase evaluation; Intestines - enzymology; Kinetics; Lactase; Magnetic Resonance Spectroscopy; Nitrophenylgalactosides - metabolism; Rats; Xylose - metabolism; Xylose - urine; β- d-Galactopyranosyl- d-xylopyranosides
• ISSN: 0008-6215; 1873-426X
• DOI: 10.1016/0008-6215(96)00113-9

By enzymatic β- d-galactosylation of d-xylose a mixture of 4-, 3-, and 2-O-β- d-galactopyranosyl- d-xyloses ( 1, 4, and 7, respectively) was obtained in 50% isolated yield. Disaccharides 1, 4, and 7 are substrates of intestinal lactase isolated from lamb small intestine with K m values of 250.0, 4.5, and 14.0 mM, respectively. The mixture was used to monitor the normal decline in lactase activity in rats that takes place after weaning. The data obtained by this method correlated with the levels of intestinal lactase activity in the same animals after being sacrificed.