Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.2.1.26 (invertase)
 4,927 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Investigation of intestinal disaccharide hydrolysis and permeability by means of a non-invasive differential sugar absorption test was performed in a family containing two siblings with primary sucrase-isomaltase deficiency. The procedure, which depends on measurement of urinary excretion ratios after the oral administration of lactose, sucrose, palatinose, lactulose and L-rhamnose, is capable of simultaneous determination of intestinal lactase, sucrase, and isomaltase activity and lactulose:rhamnose permeability. The results corresponded well with those of disaccharidase assay and histological findings in jejunal biopsy tissue obtained from the patients. Palatinose proved a satisfactory substrate for in vivo assessment of intestinal isomaltase activity. The method described provides a reliable and comprehensive assessment of intestinal disaccharide hydrolysis, and simultaneous estimation of permeability assists discrimination of primary from secondary disaccharidase deficiency. The ability to assess three different disaccharidase activities in addition to intestinal permeability by means of a single test, and the simplicity of preservation and transport of urine samples for sugar analysis, makes this a convenient, definitive method for the investigation of defective sugar absorption in both patients and population groups.
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PMID:Combined assessment of intestinal disaccharidases in congenital asucrasia by differential urinary disaccharide excretion. 237 Mar 9

No D-glucosylfructoses except sucrose, neither the alpha(1----1)- nor the alpha(1----3)- or the alpha(1----5)- or the alpha(1----6)-disaccharide possess substrate properties for beta-fructosidase from yeast. The two latter ones, leucrose and isomaltulose, however, are non-competitive (leucrose) or uncompetitive (isomaltulose, Palatinose) inhibitors of beta-fructosidase from yeast. Due to the high substrate specificity of invertase, assays of its activity have predictive power for cariological aspects of sugar substitutes carrying glycoside bonds between glucose and fructose.
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PMID:[A stepwise method of evaluating sugar substitutes--a preliminary study using enzymes. 2. Beta-fructosidase from yeast]. 354 94

Erwinia rhapontici is able to convert sucrose into isomaltulose (palatinose, 6-O-alpha-D-glucopyranosyl-D-fructose) and trehalulose (1-O-alpha-D-glucopyranosyl-D-fructose) by the activity of a sucrose isomerase. These sucrose isomers cannot be metabolized by plant cells and most other organisms and therefore are possibly advantageous for the pathogen. This view is supported by the observation that in vitro yeast invertase activity can be inhibited by palatinose, thus preventing sucrose consumption. Due to the lack of genetic information, the role of sucrose isomers in pathogenicity has not been evaluated. Here we describe for the first time the cloning and characterization of the palatinose (pal) genes from Erwinia rhapontici. To this end, a 15-kb chromosomal DNA fragment containing nine complete open reading frames (ORFs) was cloned. The pal gene products of Erwinia rhapontici were shown to be homologous to proteins involved in uptake and metabolism of various sugars from other microorganisms. The palE, palF, palG, palH, palK, palQ, and palZ genes were oriented divergently with respect to the palR and palI genes, and sequence analysis suggested that the first set of genes constitutes an operon. Northern blot analysis of RNA extracted from bacteria grown under various conditions implies that the expression of the palI gene and the palEFGHKQZ genes is oppositely regulated at the transcriptional level. Genes involved in palatinose uptake and metabolism are down regulated by sucrose and activated by palatinose. Palatinose activation is inhibited by sucrose. Functional expression of palI and palQ in Escherichia coli revealed sucrose isomerase and palatinase activity, respectively.
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PMID:Cloning and characterization of the gene cluster for palatinose metabolism from the phytopathogenic bacterium Erwinia rhapontici. 1127

This study was conducted to investigate the inhibitory effects of palatinose and Palatinit, which are disaccharides (or disaccharide alcohol) connected through an alpha-1,6-glucosyl linkage, on the hydrolysis of other carbohydrates, using an enzyme extract from the rat small intestine and a purified sucrase-isomaltase complex. Palatinose and its hydrogenated product, Palatinit, an equimolar mixture of alpha-O-D-glucopyranosyl-1,6-D-sorbitol (GPS) and alpha-O-D-glucopyranosyl-1,6-D-mannitol (GPM), inhibited the hydrolysis of sucrose and maltose. Palatinose and Palatinit also inhibited the hydrolysis of dextrin and soluble starch. Kinetic analysis of the enzymatic inhibition by GPS and GPM on sucrose hydrolysis revealed that both GPS and GPM competitively inhibit sucrase catalytic activity. These results suggest that disaccharides with an alpha-1,6-glucosyl linkage competitively inhibit intestinal alpha-glucosidases and may reduce the rate of hydrolysis of sucrose and other alpha-glucosylsaccharides.
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PMID:Inhibitory action of palatinose and its hydrogenated derivatives on the hydrolysis of alpha-glucosylsaccharides in the small intestine. 1858 10