4-O-β-spD-Galactopyranosyl-spD-xylose: A new synthesis and application to the evaluation of intestinal lactase

Rivera‐Sagredo, Alfonso; Fernández-Mayoralas, Alfonso; Jiménez‐Barbero, Jesús; Martín‐Lomas, Manuel; Villanueva, Daniel; Aragón, J. L.

doi:10.1016/s0008-6215(00)90554-8

Cited by 22 publications

(12 citation statements)

References 25 publications

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“…The 2-desoxy, 3-desoxy and 6-desoxy derivatives were synthesized [23] and assayed with lactase. The HO-2 and HO-3 groups seem to have some, although small, influence on substrate recognition, because the K, of the corresponding deoxy derivatives increases, although not significantly, with respect to that of methyl p-lactoside.…”

Section: Resultsmentioning

confidence: 99%

“…The 2'-deoxy, 3'-deoxy, 4'-deoxy and 6'-deoxy derivatives were synthesized as described elsewhere [23]. With the 2'-deoxy derivative, transformation was not observed, within the limits of the GC method, even when high concentrations of enzyme and long incubation times were used.…”

Section: Resultsmentioning

confidence: 99%

“…Phloretin was obtained by acid hydrolysis from phlorizin. The lactose analogues (Scheme 2) methyl P-lactoside (1) [18]; methyl P-cellobioside (2) [19]; methyl a-lactoside (3) [20]; 1,6-anhydrolactose (4) [21]; lactal ( 5 ) [22]; methyl 2-deoxy-j?-lactoside (6) [23] ; methyl 3-deoxy-P-lactoside (7) [23]; methyl 6-deoxy-fi-lactosidc (8) [23]; methyl 3-0-methyl-P-lactoside (9) [23]; 3-0-methyl-fi-lactose (10) [24]; methyl 4 -0 -P -~-galactopyranosyl-P-D-xylopyranoside (1 1) [23] ; 4 -0 -p -~-galactopyranosyl-D-xylose (12) [25] ; methyl 2'-deoxy-Plactoside (13) [23]; methyl 3'-deoxy-fi-lactoside (14) [23] ; methyl 4'-deoxy-P-lactoside (1 5 ) [23] ; methyl 6'-deoxy-j?-lactoside ( 3 6) [23] were synthesized as described previously. …”

Section: Substrates and Other Lactose Analoguesmentioning

confidence: 99%

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Substrate specificity of small‐intestinal lactase

Rivera‐Sagredo

Cañada

Nieto

et al. 1992

European Journal of Biochemistry

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Lactase-phlorizin hydrolase is a disaccharidase present in the small intestine of mammals. This enzyme has two active sites, one being responsible for the hydrolysis of lactose. Lactase activity is thought to be selective towards glycosides with a hydrophilic aglycon. In this work, we report a systematic study on the importance of each hydroxyl group in the substrate molecule for lactase activity. For this purpose, all of the monodeoxy derivatives of methyl b-lactoside and other lactose analogues are studied as lactase substrates. With respect to the galactose moiety, it is shown here that HO-3' and HO-2' are necessary for hydrolysis of the substrates by lactase. Using these chemically modified substrates, it has been confirmed that lactase does not behave as a typical P-galactosidase, since it does not show an absolute selectivity with respect to substitution and stereochemistry at C4' in the galactose moiety of the substrate. However, the glucose moiety, in particular the HO-6, appears to be important for substrate hydrolysis, although none of the hydroxyl groups seemed to be essential. In order to differentiate both activities of the enzyme, a new assay for the phlorizin-hydrolase activity has also been developed.Small-intestinal disaccharidases in higher animals are located in the luminal membrane of intestinal mucose where they hydrolyze the disaccharides in the diet and the oligosaccharides that arise in the intestinal lumen after a-amiIolysis of starch [l, 21. Lactase is the small-intestinal disaccharidase that splits the major 8-glycoside of the diet, lactose, to give glucose and galactose (Scheme 1). The enzyme has been the subject of considerable investigation because of its involvement in the most frequent genetically based syndrome in man, known as adult-type alactasia or lactose intolerance in the adult resulting in a remarkable decrease in lactase activity in adulthood which affects more than 33% of adult humans [I, 3,4].A biological clock appears to exist, causing a marked decline of lactase after weaning, except for individuals whose ancestors are dependent on a substantial consumption of milk and milk-derived products.It has been known for some time that, in addition to lactase activity, the enzyme carries a P-glucosidase activity refered to as phlorizin hydrolase [5-81, which is in fact a glycosylceramidase [9]. The enzyme is therefore named lactasephlorizin hydrolase or the intestinal P-glycosidase complex. We have now carried out a systematic study of the substrate specificity with respect to the lactase site of the bglycosidase complex from sheep small intestine, using chemically modified methyl P-lactoside derivatives. Methyl P-lactoside rather than lactose, has been used as a reference compound in order to simplify the analysis of the reaction mixtures. These chcmically modified substrates have been frequently used in the study of enzyme mechanisms [13 -161 and have proved extremely useful in probing the combining sites for the elucidation of specific interactions between proteins and carb...

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Substrates and Other Lactose Analoguesmentioning

confidence: 99%

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Substrate specificity of small‐intestinal lactase

Rivera‐Sagredo

Cañada

Nieto

et al. 1992

European Journal of Biochemistry

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“…We developed a new, noninvasive method based on oral administration of 4-galactosylxylose, a close structural analog of lactose, which is hydrolyzed by intestinal lactase yielding 2 physiologic products, galactose and xylose (14,15 ). d-Xylose is passively absorbed from the small intestine (16,17 ) and is accumulated in the urine (14,15 ), where it could be measured by a simple colorimetric method (18 ).…”

mentioning

confidence: 99%

“…d-Xylose is passively absorbed from the small intestine (16,17 ) and is accumulated in the urine (14,15 ), where it could be measured by a simple colorimetric method (18 ). To overcome the complexity and inefficiency of the chemical synthesis of 4-galactosylxylose, we carried out an enzymatic synthesis involving only 1 reaction step (19 ), which produced a final preparation with high yield, but consisting of a mixture of 2-, 3-, and 4-galactosylxyloses ( Fig.…”

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Noninvasive Evaluation of Intestinal Lactase with 4-Galactosylxylose: Comparison with 3- and 2-Galactosylxylose and Optimization of the Method in Rats

et al. 2006

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Background: Urinary excretion of D-xylose by suckling rats after ingestion of a mixture of 4-, 3-, and 2-galactosylxyloses reflects lactase activity in vivo. We aimed to select the most convenient of these disaccharides for detecting changes of the enzyme activity in vivo and to optimize the method. Methods: 4-, 3-, and 2-Galactosylxyloses were synthesized and purified, then orally administered to suckling rats of different ages. D-Xylose was measured colorimetrically by the phloroglucinol reaction in urine and plasma. Lactase activity was determined in extracts of small intestine mucosa with lactose, galactosylxyloses, and phlorizin as substrates. Results: D-Xylose appeared in the urine in a dosedependent manner after ingestion of any of the 3 galactosylxylose disaccharides. Correlation between D-xylose elimination and intestinal lactase activity was highest with 4-galactosylxylose (r ‫؍‬ 0.97; n ‫؍‬ 24), lower with 2-galactosylxylose (r ‫؍‬ 0.89; n ‫؍‬ 24), and lowest with 3-galactosylxylose (r ‫؍‬ 0.34; n ‫؍‬ 23). The kinetic properties of intestinal lactase accounted for these differences. D-Xylose concentration in plasma after administration of 4-galactosylxylose also correlated with lactase activity (r ‫؍‬ 0.93; n ‫؍‬ 33).

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Marine glycosyl hydrolases in the hydrolysis and synthesis of oligosaccharides

Giordano

Andreotti

Tramice

et al. 2006

Biotechnology Journal

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The marine ecosystem can be considered a rather unexplored source of biological material (e.g. natural substances with therapeutic activity) and can also be a surprising source of enzymes carrying new and interesting catalytic activities to be applied in biocatalysis. The use of glycosyl hydrolases from marine environments dates back to the end of the 1960s and was mainly focused on the development of sensitive and reliable hydrolytic methods for the analysis of sugar chains. As a result not all the benefits of a particular enzymatic activity have been investigated, especially regarding the transglycosylation potential of these enzymes for the synthesis of glycosidic bonds. In this review, the potential of marine sources will be demonstrated reporting on the few examples found in literature for the synthesis and hydrolysis of biologically relevant oligosaccharides catalyzed by glycosyl hydrolases of marine origin. Particular emphasis is given to the synthesis of glycosidic bonds, which is easy by the use of glycosyl hydrolases. Further aspects considered in this review are applications of these biocatalysts for vegetal waste treatment in recovering useful materials, for structural identification and for preparation of target materials from new purified polysaccharides, for the synthesis or modification of food-related compounds and for glycobiology related studies.

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4-O-β-spD-Galactopyranosyl-spD-xylose: A new synthesis and application to the evaluation of intestinal lactase

Cited by 22 publications

References 25 publications

Substrate specificity of small‐intestinal lactase

Substrate specificity of small‐intestinal lactase

Noninvasive Evaluation of Intestinal Lactase with 4-Galactosylxylose: Comparison with 3- and 2-Galactosylxylose and Optimization of the Method in Rats

Marine glycosyl hydrolases in the hydrolysis and synthesis of oligosaccharides

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