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)

Extracts of Streptococcus mitis ATCC 903 were analysed for beta-fructofuranosidase and alpha-glucosidase activities by isoelectric focusing in thin-layer polyacrylamide gels combined with zymogram procedures. Three bands of activity were visualized in the gels after incubation with sucrose (pI 4.05, 4.25 and 4.85) and three other bands after incubation with p-nitrophenyl alpha-D-glucopyranoside (pI 3.90, 4.45 and 4.65). The enzymes responsible for the reaction with sucrose were identified as beta-fructofuranosidases (EC 3.2.1.26) for the following reasons: identical enzyme bands were visualized in the gels after incubation with raffinose; no enzyme bands appeared in the gel after incubation with the alpha-glucosides maltose, turanose, trehalose and melezitose; and the soluble fraction hydrolysed sucrose to equimolar amounts of glucose and fructose.
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PMID:Isoelectric focusing studies on the beta-fructofuranosidases and alpha-glucosidases of Streptococcus mitis. 35 25

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

Bacterial extracts were prepared from cultures originating in chronic self-filling intestinal blind loops in rats. Their ability to remove active maltase molecules from isolated brush border membranes was studied in vitro. Twelve strains in 51 tested, belonging to one of three species, Bacteroides fragilis, Clostridium perfringens, and Streptococcus fecalis, possessed maltase-releasing activity. The ability to remove maltase correlated well with the ability to hydrolyze p-nitrophenyl-tert-butyloxycarbonyl-l-alaninate (NBA), an ester substrate rapidly hydrolyzed by elastase, but not with substrated favored by tryhsin and chymotrypsin. Maltase-releasing activity from C. perfringens was strongly inhibited by soybean trypsin inhibitor and to a lesser extent by lima bean trypsin inhibitor. Of four chloromethylketone active-site directed inhibitors tested with specificities for elastase, trypsin, and chymotrypsin, inhibition was maximal with elastase-specific inhibitors. In two species, activity was shown to be heat sensitive, and to be inhibited by concentration of the extract. In one species maltase-releasing activity was shown to be due to an enzyme of molecular weight at least 66,000 with the capacity to remove lactase, sucrase, and alkaline phosphatase, as well as maltase. The results indicate that anaerobic or facultatively anaerobic species, previously identified with the pathology of of the blind loop syndrome, contain proteases which are capable of removing components of the intestinal surface membrane. These proteases appear to have elastase-like substrate specificity and may be involved in the etiology of disaccharidase deficiency in bacterial overgrowth syndromes.
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PMID:Pathogenesis of mucosal injury in the blind loop syndrome. 35

Studies were made on the effects of intraluminal factors on the circadian rhythm and the adaptive change to diet of maltase and sucrase activities in rat small intestine. Rats given carbohydrate-free diet for 1 week showed lower specific activities of these enzymes than rats on the latter diet. Segments of jejunum, isolated as blind sacs with normal blood and nerve supplies, showed the same circadian rhythm as unligatured jejunum, but their enzyme activities were not increased by administration of carbohydrate-rich diet for 1 week. Thus it was concluded that the adaptive changes of disaccharidase activities caused by change in diet depend primarily on the presence of carbohydrate in the intestinal lumen, whereas the circadian rhythmic changes do not.
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PMID:Circadian rhythm and dietary response of disaccharidase activities in isolated rat jejunum. 35 2

In rats fed for 4, 15, and 30 days with increased amount of proteins, lipids, and carbohydrates, considerable shifts occurred in activity of enzymes of the pancreas (amylase, protease, and lipase) and small intestine (gamma--amylase, maltase group, invertase, peptidhydrolase, monoglyceriflipase). Mathematical analysis suggested a close connection between the adaptive shifts in the enzyme systems maintaining the lumen and the membrane types of digestion. The protein diet augments the proteolytic enzyme chain the lipid diet--the lipolytic chain, and the carbohydrate diet--the carbohydrate chain. The shifts should be regarded as an integrative adaptive response of the enzyme spectrum of the pancreas and small intestine to alterations in the food composition.
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PMID:[Interrelationships between the enzymatic functions of the pancreas and small intestine during adaptive processes]. 36 44

To determine whether oxytetracycline hydrochloride and the sodium salt of ampicillin have any adverse effects on the rat intestine, enteric enzyme levels and glucose transport rates were measured in vitro in rats. The intestinal transport of glucose did not differ significantly between control animals and those pretreated with ampicillin. For animals pretreated with oxytetracycline, the transport rates were significantly lower than those for the control group. The difference between the ampicillin and oxytetracycline groups, however, was not statistically significant. No significant differences in enteric levels of sucrase and maltase activity were found between any of the groups. The possibility that some antimicrobial agents may interfere with the absorption of nutrients suggested the need for caution in using these drugs in experimental animals.
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PMID:The effects of selected antimicrobials on glucose transport in the rat intestine. 37 63

The in-vivo effects of sodium deoxycholate (DOC) at low concentrations on the release of protein and some brush border hydrolases, sucrase (SA), maltase (MA), leucine aminopeptidase (LA), alkaline phosphatase (AP), have been investigated in the rat by a jejunal perfusion technique. During perfusion with DOC (0.125 or 0.25 mmol/l), enzyme release was not enhanced. After removal of DOC from the perfusion solution with 0.125 mmol/l DOC, there was a steady release of SA, MA and AP although enzyme release was increased linearly in the control and the 0.25 mmol/l DOC groups. The results also confirm the deep localization of AP within the membrane.
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PMID:Do low doses of deoxycholate modify the release of rat jejunal brush border hydrolases? 37 3

1. Jejunal biopsy specimens from three children with congenital sucrase-isomaltase deficiency were assayed for disaccharidase activity and were subjected to analytical subcellular fractionation with enzymic microanalysis. 2. By use of the highly sensitive fluorigenic modification of the disaccharidase assay, brush-border sucrase and isomaltase activities were depressed but nevertheless detectable in each child. 3. Apart from the expected decrease in brush-border alpha-glucosidase activity, the other enterocyte marker-enzyme activities were normal. 4. There were no abnormalities in the enterocytes of any child on analytical subcellular fractionation or on electron microsocopy.
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PMID:Subcellular fractionation studies of the intestinal mucosa in congenital sucrase--isomaltase deficiency. 38 73

The effect of intestinal bacterial over-growth on brush border hydrolases and brush border glycoproteins was studied in nonoperated control rats, control rats with surgically introduced jejunal self-emptying blind loops, and rats with surgically introduced jejunal self-filling blind loops. Data were analyzed from blind loop segments, segments above and below the blind loops, and three corresponding segments in the nonoperated controls. Rats with self-filling blind loops had significantly greater fat excretion than controls and exhibited significantly lower conjugated:free bile salt ratios in all three segments. Maltase, sucrase, and lactase activities were significantly reduced in homogenates and isolated brush borders from the self-filling blind loop, but alkaline phosphatase was not affected. The relative degradation rate of homogenate and brush border glycoproteins was assessed by a double-isotope technique involving the injection of d-[6-(3)H]glucosamine 3 h and d-[U-(14)C]glucosamine 19 h before sacrifice, and recorded as a (3)H:(14)C ratio. The relative degradation rate in both homogenate and brush border fractions was significantly greater in most segments from rats with self-filling blind loops. In the upper and blind loop segments from rats with self-filling blind loops, the (3)H:(14)C ratios were higher in the brush border membrane than in the corresponding homogenates, indicating that the increased rates of degradation primarily involve membrane glycoproteins. Incorporation of d-[6-(3)H]glucosamine by brush border glycoproteins was not reduced in rats with self-filling blind loops, suggesting that glycoprotein synthesis was not affected. Polyacrylamide gel electrophoresis of brush border glycoproteins from the contaminated segments indicated that the large molecular weight glycoproteins, which include many of the surface hydrolases, were degraded most rapidly. Brush border maltase, isolated by immunoprecipitation, had (3)H:(14)C ratios characteristic of the most rapidly degraded glycoproteins. The results indicate that bacteria enhance the destruction of intestinal surface glycoproteins including disaccharidases. Since alkaline phosphatase, a glycoprotein, is not affected, the destruction is selective and presumably involves only the most exposed membrane components.
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PMID:Pathogenesis of mucosal injury in the blind loop syndrome. Brush border enzyme activity and glycoprotein degradation. 41 Aug 30

1. The proteins of the intestinal microvillus membrane have been studied during post-natal development in the rat (days 12--37). 2. In suckling animals (up to age 20 days), the majority of alkaline phosphatase, glucoamylase and lactase activities in the distal half of the intestine were located in the supernatant fraction (100000 X g, 60 min). These enzymes were attached to the membrane from the proximal intestine at all ages. 3. Alkaline phosphatase, maltase and lactase activities in the supernatant fractions chromatographed in Sephadex G-200 in positions similar to the corresponding membrane enzyme. Corresponding activities for lysosomal counter-parts of maltase and lactase present in the supernatant fraction chromatographed differently. Moreover, pH optimum of the soluble enzymes was 9.2 for phosphatase and 5.5--6.0 for glycoamylase and lactase. The soluble lactase and alkaline phosphatase were inhibited minimally by p-chloromercuribenzoate, and sodium fluoride respectively. L-Phenylalanine (20 mM) did inhibit the soluble phosphatase by 90%. Thus, the soluble enzymes are not mainly of the lysosomal origin, but have characteristics of membrane-bound enzymes. 4. Polyacrylamide gel electrophoresis in sodium dodecyl sulfate revealed 18 protein bands which were present in adult membranes. Two other proteins were unique for membranes of distal intestine in suckling rats. The proteins corresponding to known enzyme activity changed as expected with age (e.g. sucrase, maltase increased, lactase decreased). Most of the other proteins were also altered in amount during development. Thus, the changes in the microvillus membrane during development in the rat are not limited to specific enzymes.
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PMID:Development of intestinal brush border membrane proteins in the rat. 41 9


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