Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: 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)

The protein induced modifications of the small bowel mucosa from ovalbumin-sensitised mouse have been studied in organ culture. A decrease in gamma-glutamyl transpeptidase, alkaline phosphatase, lactase, sucrase, and glucoamylase activities was observed in the explants cultured in the presence of ovalbumin. In contrast, a large increase of those enzymatic activities was noted in the culture media, the overall effect observed being a net stimulation of the total enzymatic activities of the culture system. The enzymes accumulated in the particulate fraction of the medium (brush border membrane fraction) suggesting an increased turnover of membrane components by a process of shedding or microvesiculation. This model serves as a useful tool in evaluating the local response of the small bowel mucosa induced by a specific protein.
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PMID:Establishment of an animal model of ovalbumin sensitised mouse to study protein induced enteropathy. 379 13

In adult sparse-fur mutant mice, ornithine transcarbamylase (OTC) activity represents only 14% of the normal values. We studied the development of this activity from birth to adult period and demonstrated that the enzyme deficiency is already fully expressed at birth, in both the liver and the small intestine of mutants. Since OTC catalyzes the conversion of ornithine to citrulline, in the presence of carbamoyl-phosphate, the effect of a disturbed ornithine metabolism on the postnatal development of the small intestine has been evaluated. The normal appearance of sucrase as well as the normal increase of glucoamylase, trehalase, and alkaline phosphatase activities are delayed in sparse-fur mice compared with controls. Moreover, normal adult values are never attained. In contrast, the normal decline of lactase activity is impaired while leucylnaphthylamidase activity is unaffected. Cell proliferation, as evaluated by [3H]thymidine incorporation into DNA and mitotic index, is less active during the 3rd wk of life in mutants. These phenomena are closely associated with a transient weak arginase and ornithine decarboxylase activity in the small intestine. Since arginase catalyzes the conversion of arginine to orthithine, thus ensuring the availability of this substrate for ornithine decarboxylase activity, these results indicate a disturbance of polyamine metabolism in mutant enterocytes with a consequent delay in postnatal differentiation and proliferation. Sparse-fur mutant mouse may therefore represent a useful animal model for evaluating the role of ornithine metabolism in the maturation process of the small intestine.
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PMID:Postnatal maturation of enterocytes in sparse-fur mutant mice. 395 97

The influence of two new 1-desoxynojirimycin derivatives, BAY m 1099 and BAY o 1248, on rat small intestinal disaccharidases (sucrase, maltase, isomaltase, glucoamylase, lactase, trehalase) and alkaline phosphatase activity has been investigated in vitro. Both compounds are very potent alpha-glucosidase inhibitors. Tested in the range of 0.1-5.0 micrograms/ml, inhibition is strongest on sucrase (up to 97.1%) and glucoamylase (up to 96.7%). BAY m 1099 also reduced (up to 56.4%) beta-galactosidase (lactase) activity. For both inhibitors a competitive type of sucrase inhibition was demonstrated (Lineweaver-Burk plot). Affinity versus sucrase was unusually tight. The Ki of BAY m 1099 versus sucrase amounted to 1.14 x 10(-7) M and of BAY o 1248 to 6.92 X 10(-8) M (Dixon plot). Both inhibitors did not impair active transport of L-leucine or methyl-alpha-D-glucoside into everted rings of rat jejunum in vitro.
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PMID:Effect of 1-desoxynojirimycin derivatives on small intestinal disaccharidase activities and on active transport in vitro. 403 92

The influence of hydrocortisone on the differentiation and proliferation of human fetal small intestine was studied. Fetal intestine (12- to 14-week gestation) was cultured during 5 days at 37 degrees C in serum-free Leibovitz L-15 medium alone or supplemented with hydrocortisone (12.5, 25, and 50 ng/ml). The addition of different concentrations of hormone did not affect the morphology of the intestinal explants. Brush border membrane hydrolytic activities, namely, sucrase, lactase, glucoamylase, trehalase, and alkaline phosphatase activities, were assayed in the intestinal tissue. A specific increase of lactase and alkaline phosphatase activities was induced by the addition of 25 and 50 ng hydrocortisone/ml culture medium. The DNA synthesis evaluated by the incorporation of [3H]thymidine was increased by the addition of 50 ng hydrocortisone/ml. The sites of incorporation into the different layers of the intestinal wall were studied by radioautography. The incorporation of the radioactive precursor occurred mainly in the epithelium and to a lesser degree in the mesenchyme and muscular layers. Labeled epithelial nuclei were located in the intervillous areas and developing crypts but not on the villi. The addition of hydrocortisone induced a significant increase of the labeling index of the epithelial cells. The present work provided for the first time some basic data on the influence of hydrocortisone on brush border hydrolytic activities and on epithelial cell proliferation of human fetal small intestine.
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PMID:Influence of hydrocortisone on human fetal small intestine in organ culture. 406 77

1. Glucose oxidase (EC 1.1.3.4), amyloglucosidase (EC 3.2.1.3), invertase (EC 3.2.1.26) and beta-galactosidase (EC 3.2.1.23) were covalently attached via glutaraldehyde to the inside surface of nylon tube. 2. The linked enzyme system, comprising invertase immobilized within a nylon tube acting in series with glucose oxidase immobilized in a similar way, was used for the automated determination of sucrose. 3. The linked enzyme system, comprising beta-galactosidase immobilized within a nylon tube acting in series with glucose oxidase immobilized in a similar way, was used for the automated determination of lactose. 4. The linked enzyme system, comprising amyloglucosidase immobilized within a nylon tube acting in series with glucose oxidase immobilized in a similar way, was used for the automated determination of maltose. 5. Mixtures of glucose oxidase and amyloglucosidase were immobilized within the same piece of nylon tube and used for the automated determination of maltose. 6. Mixtures of glucose oxidase and invertase were immobilized within the same piece of nylon tube and used for the automated determination of sucrose.
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PMID:Preparation of some immobilized linked enzyme systems and their use in the automated determination of disaccharides. 420 8

A pleiotropic mutation in Neurospora (exo-1), which confers derepression of alpha-amylase, glucoamylase, beta-fructofuranosidase, and trehalase, appears to also affect the composition of the cell wall. Segregants resulting from the backcross of exo-1 to the wild-type strain from which it derived are altered in the ratio of galactosamine to glucosamine in hydrolysates of isolated cell walls. Conidial cell walls exhibit a marked decrease in the amount of galactosamine in both exo-1 and exo-1(+) strains. Increased levels (approximately sevenfold) of amylase are found in conidia of exo-1, as compared with those of exo-1(+).
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PMID:Cell wall alterations associated with the hyperproduction of extracellular enzymes in Neurospora crassa. 426 2

The influence of hydrocortisone (10(-8)--10(-5) M) and thyroxine (10 (-9)--10(-6) M) on intestinal epithelial cell differentiation and proliferation have been studied using explants of suckling mouse jejunum maintained in serum-free organ culture. Hydrocortisone induced the appearance of sucrase activity and increased trehalase, glucoamylase, lactase and alkaline phosphatase activities. Thyroxine was completely ineffective at all the concentrations used. None of these hormones affected the mitotic activity or the 3H-thymidine incorporation into DNA. These results demonstrate that hydrocortisone but not thyroxine acts directly on intestinal brush border membrane differentiation and that both hormones do not influence the proliferation of the epithelial cells during postnatal development.
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PMID:Comparative study of the effect of hydrocortisone and thyroxine on suckling mouse small intestine in organ culture. 614 44

In the pigeon, 70-80% of the activities of maltase (alpha-D-glucoside glucohydrolase EC 3.2.1.20), sucrase (alpha-glucohydrolase, EC 3.2.1.48), isomaltase (dextran 6-alpha-D-glucan hydrolase, EC 3.2.1.10) and glucoamylase (1,4-alpha-D-glucan glucohydrolase, EC 3.2.1.3) were found to be localized in the brush-border membrane of intestinal epithelial cells. Of the total glycosidase activities in the mucosal homogenate, nearly 60 to 70% were recovered in the microsomal (105 000 X g) fraction, about 30% in the mitochondrial (22 000 X g) fraction and less than 5% from the cytosol (105 000 X g supernatant) fraction. The hydrolases were solubilized by digestion with papain but not with trypsin, and the phosphate ion had a protective effect in the solubilization. Amongst detergents, Triton X-100 but not sodium deoxycholate, was found to truly solubilize these enzymes.
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PMID:Studies on the intestinal disaccharidases of the pigeon. II. Subcellular localization and solubilization. 618 28

Sucrase-isomaltase (S-I) and maltase-glucoamylase (M-G) of the brush border have been purified to electrophoretic homogeneity from the pigeon small intestine. Heat-inactivated enzymes of crude homogenates of the pigeon intestinal mucosa, papain-solubilized enzymes and those obtained after chromatographic fractionation behaved in an identical manner. Depending on their sensitivity to heat treatment, the disaccharidases were identified to consist of two maltases; one, the heat-labile maltase, and the other, the heat-stable maltase. Sucrase and isomaltase constituted the thermolabile maltase and could be distinguished from each other. Maltase and glucoamylase formed the thermostable maltase the activities of which however, remained inseparable. Based on these results and in accordance with the nomenclature suggested by Dahlqvist & Telenius (1969), the pigeon intestinal disaccharidases were classified as follows: Maltase Ia = isomaltase, Maltase Ib = sucrase, and Maltase II = glucoamylase. DEAE-Cellulose chromatography did not resolve the two enzyme complexes but gel filtration of the active fractions recovered from the former step, resulted in their separation into two distinct peaks. Sucrase, isomaltase and a part of the maltase activity were recovered in the first peak which eluted close to the void volume. Glucoamylase and the remaining maltase activity were recovered in the second peak which appeared to have been retarded on the column because they were eluted much more slowly. The S-I and M-G complexes have an apparent molecular weight of 195 kd and 209 kd as determined by their gel-filtration pattern on Sepharose 6B. S-I hydrolysed alpha-glucosides such as maltose, sucrose and palatinose with a Km of 3.12 mM, 8 mM and 8.36 mM respectively and did not attack starch or dextran. In contrast, M-G catalysed the hydrolysis of starch, amylose and maltose with a Km of 3.12 mM, 7.59 mM and 3.52 mM respectively, and had no action on sucrose or palatinose. Both S-I and M-G were glycoproteins, and were inhibited by Ag+, Hg2+ and Tris but not by p-hydroxymercuribenzoate, iodoacetamide or imidazole. Na+ on the other hand activated both the enzyme complexes by about 20-25%. It is suggested that the molecular and catalytic properties of intestinal disaccharidases of pigeons do not differ considerably from those of Mammals.
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PMID:Studies on the intestinal disaccharidases of the pigeon. III. Separation, purification and properties of sucrase-isomaltase and maltase-glucoamylase. 620 6

Acarbose is known to inhibit glucoamylase, maltase and sucrase. Our aim was to test whether it would also inhibit glucosyltransferase (GTF), to determine the type of inhibition and to compare the inhibitor potency of acarbose with that of nojirimycin and deoxynojirimycin, two other glucosidase inhibitors. Enzyme inhibition was measured either by chemical assay or by incorporation of radioactivity into product. Acarbose effectively inhibited the synthesis of polysaccharide by GTF from strains of Streptococcus mutans and Streptococcus sanguis, but not by fructosyltransferase from Streptococcus salivarius. Acarbose and 1-deoxynojirimycin were more potent inhibitors of GTF than maltose, nojirimycin or various amino sugars. The mechanism of action of these compounds is consistent with competitive inhibition.
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PMID:Inhibition by acarbose, nojirimycin and 1-deoxynojirimycin of glucosyltransferase produced by oral streptococci. 622 60


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