Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.2.1.21 (beta-glucosidase)
 3,280 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Dog enterocyte brush border proteins have been studied after a 75% proximal resection of the small bowel. This study was carried on microvillar membrane preparations purified from ileal mucosa sampled before and after regeneration on neighbouring intestinal segments, each animal acting as its own control. After six weeks of regeneration a statistically significant decrease of the following enzyme specific activities was observed: lactase, cellobiase, maltase, sucrase, palatinase, dextranase, trehalase, alkaline phosphatase, aminopeptidase and gamma-glutamyl transferase. Analysis of brush border proteins by polyacrylamide gel electrophoresis in presence of sodium dodecyl sulphate have shown after regeneration a decreased rate for the proteins with a molecular weight higher than 100,000 daltons. Modifications of electrophoretic patterns seem to be related to the specific activity decreases observed for brush border enzymes after regeneration, since the molecular weight of these enzymes were found between 116,000 and 285,000 daltons, after gel filtration.
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PMID:Effect of massive proximal small bowel resection on intestinal brush border membrane proteins in the dog. 8 27

Membrane-bound enzymes have certain specific differences compared with soluble enzymes. Membrane-binding often enables greater catalytic activity of associated enzymatic reactions, their regulation by low molecular weight substances (substrates and allosteric effectors, hormones) and compartmentation, etc. On the other hand, the binding of enzymes to membranes causes considerable difficulties as regards their isolation and the determination of their homogeneity and substrate specificity. Membrane enzymes provide a unique opportunity for studying the biogenesis of membranes and their physiological properties, however. These problems are discussed in relation to two types of membranes--the inner mitochondrial membrane and the membrane of the brush border of the small intestine. An example of the utilization of immunochemical methods is given in the results of a study of biosynthesis of the cytochrome oxidase complex in yeast cells. In the case of the brush border of the mammalian small intestine, the fact that certain enzymes, which are also of clinical significance from the aspect of congenital genetic defects, can be isolated only as complexes, constitutes a very real problem. This applies particularly to the sucrase-isomaltase complex and the lactase-beta-glucosidase complex. Solving questions of substrate specificity is of significance for the choice of a suitable analytical or histochemical method. The common regulation of these complexes gives an insight into the problems of membrane biogenesis, however. Immunochemical methods can be employed as sensitive criteria to support biochemical and morphological studies. Collaboration between the biochemist and histochemist proved especially valuable when determining the substrate specificity of enzymes (glycosidases) in relation to histochemical substrates, when applying histochemical methods for detecting enzymatic activity in immunoprecipitates and acrylamide gels and in immunohistochemical studies of the localization and developmental differentiation of the enzymes of the brush border of the small intestine.
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PMID:Biochemistry and immunochemistry of membrane-bound enzymes. 9 30

Intestinal mucosa from 40 patients obtained by fiber-endoscopic biopsy was assayed for disaccharidases to determine suitability of this tissue for assay. The combined specimens from each patient provided 4.7-38.7 mg of tissue, adequate in all instances for duplicate determinations of protein, lactase, sucrase, and maltase. Tissue remained for assays of palatinase in 39 instances, trehalase and cellobiase in 37, and alkaline phosphatase in 22 cases. Twenty-four subjects had normal lactose tolerance tests and normal sucrase/lactase ratios. Thirteen patients with abnormal oral lactose tolerance tests were identified as having a primary low lactase activity on the basis of elevated sucrase/lactase ratios. This ratio was most helpful in making the diagnosis of a primary low lactase, since the mucosal specimens were not obtained from comparable areas. Tissue from three subjects with an abnormally low maltase was unsuitable for diagnosis. Endoscopic biopsy of mucosa appears to be satisfactory for disaccharidase assays in most instances.
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PMID:Adequacy of endoscopic biopsy specimens for disaccharidase assays. 10 20

The activity of the membrane-bound enzymes of the microvillous zone of the entreocytes (maltase, sucrase, trehalase, lactase, cellobiase, alkaline phosphatase and leucylaminopeptidase) was studied in mucosal smears from the proximal jejunum, ileum, caecum and sigmoid flexure in a group of control (C) (8) and germ-free (GF) (7) rabbits. The trypsin and chymotrypsin activity of the contents of the ileum, caecum and sigmoid flexure was studied in 6 C, 5 GF and 5 monocontaminated (MC) rabbits. In summing up it can be stated that the individual membrane-bound enzymes have a different gradient in the various intestinal segments of C and GF rabbits and that they differ reciprocally in character. The maximum statistically significant differences between GF and C rabbits were found in the ileum; in the jejunum they were somewhat smaller and in the caecum smaller still (in this localization the difference was C versus GF). Striking differences in the proportion of the individual disaccharidases were found inthe jejunum and ileum of C rabbits compared with GF rabbits, in which, in both these segments of small intestine the relationship maltase greater than sucrase greater than trehalase greater than lactase was preserved. The proteolytic activity of the intestinal contents likewise had a different gradient character in C, MC and GF rabbits. The maximum activities (especially trypsin) were found in MC animals. The microbial flora is one of the factors regulating the enzymatic activities of the microvillous zone of the enterocytes and it also significantly influences the proteolytic activity of the intestinal contents. This influence is particularly marked in the distal part of the alimentary tube.
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PMID:Digestive enzymes of the mucosa of the small intestine and trypsin and chymotrypsin proteolytic activity of the intestinal contents of germ-free, monocontaminated and conventional rabbits. 35 55

A close relationship exists between relative disaccharidase activities (maltase, sucrase, trehalase, palatinase, turanase, lactase, and cellobiase) in amniotic fluid and corresponding jejunal mucosa of five human fetuses (16 to 21 weeks of gestation) suggesting that these intestinal enzymes pass into amniotic fluid. Serial determination of disaccharidase activities in amniotic fluid samples collected between 10 and 42 weeks of gestation showed maximum mean activities at 14 to 17 weeks of gestation and a rapid drop to less than 12 per cent maximum values at about 22 weeks. This drop is probably caused by combined effects of decreased extrusion rate of intestinal disaccharidases and increased reabsorption of the enzymes in swallowed amniotic fluid with fetal development.
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PMID:Developmental patterns of intestinal disaccharidases in human amniotic fluid. 64 87

Intestinal mucosa and pancreas from purebred Beagle dogs were assayed for carbohydrase activity, using several methods of tissue treatment. The enzymes found and studied were alpha-amylase, sucrase, lactase, amyloglucosidase, cellobiase, maltase, and isomaltase. Experiments using polyacrylamide gel columns and heat inactivation showed the presence of an isozyme of maltase which degrades isomaltose. This activity had not been previously demonstrated in dogs. An optimal standard procedure is presented for the preparation and assay of canine digestive enzymes. A statistical analysis of variance of the results showed that the variance was primarily associated with differences among dogs and not by variance within the procedure. When the different extraction procedures were used, results indicated that the level of enzymes detected differed with the method of treatment.
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PMID:Detection and definition of canine intestinal carbohydrases, using a standardized method. 88 14

Rats with chronic uremia following five-sixths nephrectomy showed a significant fall in the sucrase and maltase activities in the small intestinal mucosa, the lactase and cellobiase activities in contrast remained uninfluenced. The activity of the L-leucyl-L-proline and L-methionyl-L-proline dipeptidases in the small intestinal mucosa was significantly increased, while the activities of seven other dipeptidases studied were unaffected. The mucosal protein and DNA content likewise remained unchanged. Occasional slight alterations of the mucosa were the only finding at histology.
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PMID:Activities of intestinal enzymes in experimental chronic renal insufficiency. 88 89

Lactase and cellobiase were detectable in the fetal intestine by the 3rd month of gestation, and although there was little change by the 9th month, maximal levels were reached at birth and steadily declined after 4 months. Conversely maltase, sucrase and trehalase were barely discernible in the fetus, maltase being present at low levels at birth, but all increased during the suckling period to attain adult levels by 7 months of age. Alkaline phosphatase activity matured earlier than did disaccharidase activity. Mucosal enzymes other than alkaline phosphatase were virtually absent from meconium and the large intestine. Continued ingestion of lactose could be detrimental in foals suffering from severe diarrhoea.
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PMID:The development and distribution of mucosal enzymes in the small intestine of the fetus and young foal. 106 Aug 71

Ethanol feeding to rats for 40 days enhanced (p < 0.001) the activities of alkaline phosphatase, sucrase, gamma-glutamyltransferase (GTP), and p-nitrophenyl (PNP)-beta-D-galactosidase (p < 0.05) with no change in leucine amino peptidase (LAP) and PNP-beta-D-glucosidase activities in intestine compared with control rats. The activities of alkaline phosphatase, sucrase, and GTP were diminished (p < 0.01) in ethanol-fed malnourished rats. There was no change in LAP activity, but the levels of glucosidase and galactosidase were elevated under these conditions. Brush-border sialic acid, fucose, hexose, and hexosamine contents were elevated in ethanol-fed protein-deficient animals. Ethanol administration to normally fed rats elevated the membrane sialic acid and hexose contents, reduced fucose content, and had no effect on brush-border hexosamine content compared with the control group. These results are in agreement with data on lectin binding to brush borders under these conditions. Alcohol ingestion reduced the incorporation of [14C]-glucosamine into brush borders in rats maintained on an 18% protein diet but augmented the incorporation of [14C]-glucosamine and [14C]-mannose in protein-malnourished membranes. These observations suggest that nutrition status influences the sensitivity of microvillus membrane glycosylation to ethanol feeding in rat intestine.
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PMID:Chronic ethanol feeding and microvillus membrane glycosylation in normal and protein-malnourished rat intestine. 142 85

The effects of variation in dietary protein content have been investigated on brush border glycosylation and enzyme activities in mice small intestine. The comparison of different parameters was made between the mice fed 30% (high protein, HP) and 18% protein (pair-fed, PF, and ad libitum-fed) for 21 days. The activities of brush border sucrase, lactase, p-nitrophenyl (PNP)-beta-D-glucosidase and PNP-beta-D-galactosidase were reduced in the HP diet-fed mice compared to PF and ad libitum-fed controls. Alkaline phosphatase and leucine amino-peptidase activities were significantly enhanced while gamma-glutamyl transpeptidase activity was unaltered under these conditions. Total hexoses and sialic acid content in the brush borders were reduced significantly in the test group compared to the controls while hexosamine and fucose contents remained essentially similar in different groups. The results on the binding of wheat germ agglutinin and Ulex europaeus agglutininI to microvillus membranes corroborated the chemical analysis data on sialic acid and fucose contents of the membranes. Peanut agglutinin binding was enhanced in mice from the HP group. Incorporation of (14C)-mannose into membranes was significantly less in HP diet-fed mice. These results indicate that the feeding of HP diet to mice brings about marked alterations in small intestinal epithelial cell surface glycosylation and enzyme functions.
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PMID:Intestinal epithelial cell surface glycosylation in mice. I. Effect of high-protein diet. 149 56


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