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)

Suspensions of sequentially isolated villus and crypt cells were obtained in order to study certain biochemical changes associated with differentiation of epithelial cells in the small intestine of the mouse. Microscopic observation of the various cell fractions reveals that the epithelial cells detach as individual cells or small sheets of epithelium from the tip to the base of the villus, whereas cells in the crypt regions are separated as entire crypt units. The isolated cells retain their ultrastructural integrity as judged by electron miscroscopy. Chemical characterization of the various fractions shows that the total cellular protein content, expressed in activity per cell, remains relatively constant throughout the villus region followed by a noticeable drop in the crypt zone. On the other hand, sharp variations in values of cell DNA content are observed in the crypt zone depending on the reference of activity being used. Activity profiles of several brush border enzymes confirm the biochemical changes that occur during the migration of cells from the crypt to the villus tip, as observed in other species, with maximum activity of sucrase in the mid-villus region, of glucoamylase, trehalase, lactase and maltase in the upper third region, and of alkaline phosphatase at the villus tip. Forty-eight-hour suspension cultures of cell fractions corresponding to cells at the base of the villus and crypt zones show a moderate decrease in protein and enzyme activities to approximately 70% of their original value, with DNA content remaining stable throughout the incubation period. The use of biochemical activities as indicators of cellular integrity during cell culture is discussed.
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PMID:Characterization of isolated villus and crypt cells from the small intestine of the adult mouse. 741 92

The hydrolysis of maltose and isomaltose and of sucrose and isomaltose at two different catalytic sites of sucrase-isomaltase has been demonstrated. Maltose and sucrose are competing for the same catalytic center. This competing can be described by alternative substrate kinetics. Steady-state kinetic parameters Km and k0 (maximal reaction velocity per mol enzyme) for linear alpha-1,4 and alpha-1,6 glucosyloligosaccharides has been determined. Using these parameters subsite affinities for the catalytic sites of sucrase and isomaltase were computed. The different numbers of subsites for sucrase (2 subsites) and isomaltase (4 subsites) indicate, that the binding patterns for maltooligosaccharides and isomaltooligosaccharides are different. That means that for sucrase unproductive enzyme-maltooligosaccharide complexes are definitely less probable than the productive one. As in human small intestinal glucoamylase-maltase in the isomaltase moiety four subsites can be evaluated with affinity values (Ai): A1 = 2.6 (+/- 0.91), A2 = 13.8 (+/- 0.70), A3 = 1.1 (+/- 0.13) and A4 = 1.5 (+/- 0.13) kJ/mol using isomaltooligosaccharides. The two subsites of sucrase are evaluated to be A1 = 4.9 (+/- 0.70) and A2 = 16.7 (+/- 0.51) kJ/mol using maltooligosaccharides. The four subsite model for isomaltase and glucoamylase-maltase is an indication that these two enzymes are mechanistically homologous in binding linear glucosyl-oligosaccharides.
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PMID:Human small intestinal sucrase-isomaltase: different binding patterns for malto- and isomaltooligosaccharides. 762 34

Mucosal surface area, protein, DNA and RNA content, [3H]-thymidine incorporation, total activity of glucosidases, peptidases, phosphatases and transaminases were measured in the duodenum and in the middle and lower parts of the small intestine of the domestic pigeon Columba livia. Mucosal surface area, protein, nucleic acid content and [3H]-thymidine incorporation were significantly higher in the duodenum and in the middle part of the small intestine than in the lower part. Whereas the activities of alkaline phosphatase, sucrase, cellobiase and lactase were significantly higher in the middle part of the small intestine, those of maltase, glucoamylase and leucine aminopeptidase were significantly higher in the lower part. It is concluded that in Columba livia small intestine, regional differences are more pronounced between the middle and the lower parts of the small intestine than between this middle part and the duodenum.
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PMID:Regional differences along the small intestine of the pigeon (Columba livia): histobiochemical evidences. 769 Dec 16

Microbial endoglycosidases are useful for elucidating the structure and function of the oligosaccharide chains of glycoconjugates. Most of the microbial endo-beta-N-acetylglucosaminidases including Endo-H can preferentially act on high-mannose type chains of asparagine-linked oligosaccharides of various glycoproteins. Among them, Flavobacterium sp. enzyme is produced in large amounts by the inducing cultivation. Using this enzyme, the role of oligosaccharide chains in various microbial glycoenzymes such as Rhizopus glucoamylase, and yeast invertase was examined. The findings suggested that the oligosaccharide chains of them are essential participants in the stabilization of the enzyme and in the protection from proteolytic inactivation. Novel endo-beta-N-acetylglucosaminidases were also found in the culture broths of microorganisms. Unlike most microbial endo-beta-N-acetylglucosaminidases, Endo-M of Mucor hiemalis could act on a complex type oligosaccharide chains, which is similar to Endo-F2 in multiple form of Endo-F from Flavobacterium meningosepticum. The complete amino acid sequences of Endo-F1, -F2, -F3, -H, and Flavobacterium sp. enzyme were determined. All of them had two highly conserved regions common to a number of chitinases. Endo-alpha-N-acetylgalactosaminidase which hydrolyzes the O-glycosidic linkages in glycoproteins was found in the culture broth of only a few microorganisms. The production of Alcaligenes sp. enzyme was highly induced by the addition of porcine gastric mucin in the culture medium. There is some evidence that endo-alpha-N-acetylgalactosaminidases may recognize not only the glycon but also the aglycon amino acids.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Microbial endoglycosidases for analyses of oligosaccharide chains in glycoproteins. 782 34

Exogenous glucocorticoids administered during the first two postnatal weeks are capable of eliciting precocious maturation of the rat intestine. However, it is not known whether this represents an alternative developmental pathway or is essentially an advancement of normal ontogeny. The goal of the present study was to address this question using the thymidine analogue 5-bromo-2'-deoxyuridine (BrdU), which is known to selectively inhibit differentiation in a number of tissues. Intestinal development was assessed by following changes in sucrase, trehalase, glucoamylase, and lactase activities. The first experiment assessed whether BrdU has any influence on the cellular differentiation that occurs continuously along the crypt-villus axis. After administration of BrdU to suckling and mature animals, there was no effect on lactase and sucrase activities, respectively. Thus BrdU does not inhibit crypt-villus differentiation in either the suckling or mature jejunum. In the second experiment, dexamethasone was used to induce precocious maturation in the rat jejunum on day 10. BrdU treatment significantly inhibited glucocorticoid-induced elevation of sucrase, trehalase, and glucoamylase but had no effect on the lactase activity. In contrast, treatment with BrdU during normal development significantly accelerated the ontogenic rise of sucrase and trehalase as well as the ontogenic decline of lactase. The acceleration of development was also seen in adrenalectomized rats, indicating that it is the glucocorticoid-independent component of normal intestinal ontogeny that is activated by BrdU. The opposite effect of BrdU on glucocorticoid-induced precocious maturation suggests that such maturation involves different molecular mediators than normal ontogeny.
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PMID:Distinguishing normal and glucocorticoid-induced maturation of intestine using bromodeoxyuridine. 784 Jan 97

Nocardia delipidated cell mitogen (NDCM) was given intragastrically (200 micrograms/animal) to 2-month-old germ-free (GF) and conventionally (CV) reared AVN rats. On day 4, enzymatic activities of enterocyte brush border membrane vesicles (BBMV) isolated from jejunal scraping were measured. The results indicated that activities of sucrase, lactase and glucoamylase in BBMV were stimulated following NDCM treatment. The most pronounced increase of enzymatic activities was found in GF rats. In contrast to CV rats, GF rats do not express MHC class II on epithelial cells during their life. NDCM treatment induced MHC class II expression in enterocytes from GF rats. The levels of IgA and IgG in sera from NDCM-treated CV rats did not change significantly. The level of IgG in sera of GF rats was found to be enhanced after NDCM treatment. Markedly increased incorporation of 3H-thymidine by spleen lymphocytes stimulated with Con A in vitro was observed only in NDCM-treated GF rats. 3H-uridine incorporation into Con A-stimulated lymphocytes of GF rats was decreased after NDCM treatment.
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PMID:Stimulation of enterocyte enzymatic activities, MHC class II expression and other immunological factors after oral treatment with Nocardia delipidated cell mitogen in germ-free rats. 792 98

This study aims to determine the effect of glucose and glucose polymers (GP) from corn in oral rehydration solutions (ORS) on disaccharidases and morphometric measurements in small intestinal mucosa of rats. ORS containing standard composition of salts as in WHO ORS and 2, 5, or 10 per cent glucose or GP [initial glucose polymers, long chain (> 9 molecules) and short chain (2-9 molecules) glucose polymers] from corn were infused into the duodenum of 72 Sprague-Dawley rats (250-350 g). Six rats were sham operated as controls. The levels of lactase, sucrase, maltase, palatinase, and glucoamylase enzymes were higher in rats infused with ORS-containing glucose or GP than control rats. Villus height, villus width, and crypt height in corresponding segments of duodenum, jejunum, and ileum were not significantly different between rats perfused with ORS containing glucose polymers from corn and those with ORS containing glucose. ORS containing GP from corn have no adverse effects on small intestinal enzymes and morphometric measurements.
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PMID:Effect of perfusion of oral rehydration solutions containing glucose polymers from corn on disaccharidases and mucosal morphology in rat small intestines. 807 18

To determine the prevalence of short polymers of glucose and starch malabsorption caused by small intestinal glucoamylase deficiency in children with chronic diarrhea, we studied small bowel biopsy specimens from 511 children (aged 1 month to 9 years) with chronic diarrhea evaluated at 54 medical centers. Glucoamylase and disaccharidase (lactase, sucrase, maltase, and palatinase) enzyme assays were performed. Of the 511 children, 15 had glucoamylase deficiency. Six who had significant small intestinal mucosal injury and disaccharidase deficiencies were defined as having secondary glucoamylase deficiency; the other nine patients with normal mucosal morphologic features were defined as having primary glucoamylase deficiency. Secretin tests showed normal pancreatic amylase values for age in all seven children tested. Four of them had abnormal findings on tolerance tests for starch and short polymers of glucose (rise in blood glucose concentration: < 20 mg/dl) and reducing substances in stools, and three of these four had symptoms of intolerance (abdominal distention, flatulence, and diarrhea). All seven patients responded to a starch elimination diet. After reintroduction of a starch diet, diarrhea recurred in four patients; this was alleviated 48 hours after reelimination of starch. We conclude that intestinal glucoamylase deficiency is present in some patients with chronic diarrhea.
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PMID:Small intestinal glucoamylase deficiency and starch malabsorption: a newly recognized alpha-glucosidase deficiency in children. 815 67

This study was directed to determine the extent of variability in structure or expression of intestinal disaccharidase [gamma-glucoamylase (gamma-GA), sucrase-isomaltase (SI), and lactase] between different strains of mice. Reduced levels of sucrase activity (approximately 20 U/g of protein) were observed in three strains of mice belonging to the CBA/Ca lineage. Four other strains of mice analyzed exhibited higher levels of sucrase activity (approximately 50 U/g of protein). Decreased levels of sucrase in CBA/Ca mice were not associated with decreased levels of activity associated with the isomaltase subunit or with decreased levels of SI mRNA expression. High-performance liquid chromatographic gel filtration, heat inactivation, and kinetic analysis indicated that the differences between strains in sucrase activity might be attributed to structural differences in the sucrase subunit of the SI complex, thus rendering it more susceptible to cleavage and inactivation. However, no differences in kinetic properties of the sucrase subunit were observed between strains. Murine gamma-GA was found to account for a greater proportion of maltase activity (approximately 70%) than that observed in other species (i.e., approximately 20%). In addition, CBA/Ca mice were found to be deficient in intestinal maltase activity (approximately 60 U/g) compared with the other strains studied (approximately 300 U/g).
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PMID:Murine intestinal disaccharidases: identification of structural variants of sucrase-isomaltase complex. 827 65

A diastatic strain of Saccharomyces cerevisiae producing the STA2-encoded extracellular glucoamylase (GA) in a pronounced glucose-repressible fashion was used as a parent for generating mutants with reduced GA activity under normal conditions of derepression. In addition to mutations in STA2, five other recessive mutations were identified which fell into four complementation groups designated haf1 through haf4. RNA blot analysis suggested that the haf mutations confer defects in STA2 transcription. The haf mutants were pleiotropically defective in utilization of alternative carbon sources and resembled the snf (sucrose non-fermenting) mutants identified previously as unable to derepress the expression of the SUC2 gene encoding invertase. We present evidence strongly suggesting that haf1 = snf2, haf3 = snf1 and haf4 = snf5. By phenotypic criteria, the postulated HAF2 gene (which is none of the SNF genes tested) appears to be similar to SNF2, SNF5 and SNF6, and is possibly a non-redundant extension of this group of functionally related SNF genes.
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PMID:Genes required for derepression of an extracellular glucoamylase gene, STA2, in the yeast Saccharomyces. 832 16


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