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 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

In a child with hereditary sucrase-isomaltase deficiency immunoreactive enzyme was present in the intact duodenal mucosa. Polyacrylamide gel electrophoresis carried out with membrane fragments of an intestinal biopsy showed an abnormal protein band without enzyme activity. The mucosa had a relatively high residual isomaltase activity which was recovered from the gel in a position suggesting higher than normal molecular weight. The results indicated that in this patient the primary structural defect was in the sucrase moiety which was enzymatically inactive. The isomaltase subunits may have aggregated into a large molecular weight complex because of unavailability of their partners. The observation also provided evidence for separate biosynthesis of the two moieties of the sucrase-isomaltase complex.
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PMID:The brush border membrane in hereditary sucrase-isomaltase deficiency: abnormal protein pattern and presence of immunoreactive enzyme. 41 77

Acid trehalase was purified from the yeast suc2 deletion mutant. After hydrophobic interaction chromatography, the enzyme could be purified to a single band or peak by a further step of either polyacrylamide gel electrophoresis, gel filtration, or isoelectric focusing. An apparent molecular mass of 218,000 Da was calculated from gel filtration. Polyacrylamide gel electrophoresis of the purified enzyme in the presence of sodium dodecyl sulfate suggested a molecular mass of 216,000 Da. Endoglycosidase H digestion of the purified enzyme resulted after sodium dodecyl sulfate gel electrophoresis in one distinct band at 41,000 Da, representing the mannose-free protein moiety of acid trehalase. The carbohydrate content of the enzyme was 86%. Amino acid analysis indicated 354 residues/molecule of enzyme including 9 cysteine moieties and only 1 methionine. The isoelectric point of the enzyme was estimated by gel electrofocusing to be approximately 4.7. The catalytic activity showed a maximum at pH 4.5. The activity of the enzyme was not inhibited by 10 mM each of HgCl2, EDTA, iodoacetic acid, phenanthrolinium chloride or phenylmethylsulfonyl fluoride. There was no activation by divalent metal ions. The acid trehalase exhibited an apparent Km for trehalose of 4.7 +/- 0.1 mM and a Vmax of 99 mumol of trehalose min-1 X mg-1 at 37 degrees C and pH 4.5. The acid trehalase is located in the vacuoles. The rabbit antiserum raised against acid trehalase exhibited strong cross-reaction with purified invertase. These cross-reactions were removed by affinity chromatography using invertase coupled to CNBr-activated Sepharose 4B. Precipitation of acid trehalase activity was observed with the purified antiserum.
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PMID:Purification and characterization of acid trehalase from the yeast suc2 mutant. 328 51

A soluble acid invertase activity isolated from Helianthus tuberosus (Jerusalem artichoke) shoots and analyzed by immunochromatography using polyclonal yeast antibodies, represents around 5% of the total invertase activity. This invertase isoenzyme was also isolated from dormant tuber parenchyma. In these partially dormant tissues, the specific activity of this isoenzyme is low suggesting a partial inactivation of the invertase molecules. Polyacrylamide gel electrophoresis of immunopurified fractions yields similar levels of the 58 kDa polypeptide both in shoots and dormant tubers, but with much lower activity of the enzyme in the tubers. A cDNA library was constructed in pUEX 1 from poly (A)+ RNA extracted from Jerusalem artichoke tubers. This library was screened for invertase using (i) a Bacillus subtilis invertase DNA probe and (ii) anti-yeast invertase antibodies. A recombinant clone of approximately 1.8 kb size was selected by these two methods. Using Northern blots, a temporal sequence in the expression of invertase gene was observed during the breaking of dormancy with the main level after 8 weeks of cold treatment at 4 degrees C. A 2.5 kb transcript was detected, translation of which would yield a 97 kDa polypeptide representing the precursor of Jerusalem artichoke invertase.
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PMID:Molecular cloning and physiological analysis of an invertase isoenzyme in Helianthus tissues. 751 Oct 14

Typically, pathogenesis of the hemibiotroph Colletotrichum graminicola and defense responses of its host, Zea mays, are studied on young leaves. Equivalent studies have not been performed with leaves undergoing senescence, a situation that is relevant in the field. We discovered that, in contrast to anthracnose symptoms formed on young and mature leaves, green islands reminiscent of those known from obligate biotrophs were formed on senescing leaves. Microscopy revealed that the fungus grew in both symptoms from the epidermis towards the bundle sheath. In green islands, tissues remained intact for an extended time period. Imaging PAM (pulse-amplitude-modulation) fluorescence analyses revealed that photosynthesis is transiently maintained at green islands but declined in tissue surrounding the infection. In younger leaves however, photosynthesis was reduced only at infection sites. Support for the local modification of host physiology came from quantitative reverse transcription-polymerase chain reaction analyzing gene expression at high spatial resolution. Decreased transcript levels of the senescence markers see1 and ccp1 corroborated a pathogen-induced delay of senescence. Expression of several genes encoding proteins involved in photosynthesis was strongly reduced by infection. In contrast, transcript levels of incw1, encoding a cell-wall invertase, were increased 70-fold at green islands, suggesting that C. graminicola induced carbon sinks in senescing tissue.
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PMID:The hemibiotroph Colletotrichum graminicola locally induces photosynthetically active green islands but globally accelerates senescence on aging maize leaves. 2052 51