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)

A sucrase from honey bees (Apis mellifera) which precipitates between ammonium sulfate saturations of 50 and 70% (5 mg protein per millilitre) and which makes up the major portion of the sucrases of honey bees was purified to homogeneity as shown by several criteria. A large part of the sucrase was found in the head while most of the rest was in the abdomen (a small amount was in the thorax). The enzyme precipitated between the same values of ammonium sulfate saturation as did the sucrase in honey and honey sucrase exhibited kinetics very similar to those of this enzyme. The enzyme was found to be a relatively nonspecific alpha-glucosidase and was shown to have transglucosidase activity. The production of glucose from sucrose was rectilinear when plotted by the Hofstee method at low substrate concentrations but decreased at high sucrose concentrations. The production of fructose was rectilinear throughout the concentration range used. The production of both glucose and rho-nitrophenol when rho nitrophenyl alpha-D-glucoside was the substrate was linear by the Hofstee plot. These effects were found to be due to transglucolysis and a mechanism of action is proposed. Amino acid and amino sugar analyses indicated that the sucrase was a glycoprotein. The molecular weight was found to be between 51000 and 82000 by three different methods and an so20.w value of 4.0 S was obtained. There was no evidence for subunit structure. Tests of the enzyme under various denaturation conditions did not reveal any unusual stabilities. The sucrase bound very tightly to a hydrophobic column. Iodoacetic acid decreased the activity of the sucrase but a large concentration was needed to bring about a 50% activity loss. Reducing agents caused some activity declines. Diethyl pyrocarbonate activated the enzyme.
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PMID:Physical, chemical, and enzymatic studies on the major sucrase of honey bees (Apis mellifera). 0 3

The initial step of disaccharide dissimilation by Actinomyces viscosus serotype 2 strain M-100 was studied. Sucrase activity was found in the 3,000 X g particulate fraction and the 37,000 X g soluble fraction of the cells, whereas lactase activity was found almost exclusively in the 37,000 X g soluble fraction. Neither sucrase nor lactase activity was appreciable in the culture liquor. Sucrose phosphorylase, alpha-glucosidase, and polysaccharide synthesis activities were not observed in the soluble cell fraction. The sucrase was identified as invertase (EC 3.2.1.26; beta-D-fructofuranoside fructohydrolase). The lactase was identified as beta-galactosidase (EC 3.2.1.23; beta-D-galactoside galactohydrolase). The enzymes in the 37,000 X g soluble fraction were separable by diethylamino-ethyl-cellulose chromatography, giving one beta-galactosidase peak and one major and one minor invertase peak. Acrylamide gel electrophoresis showed different electrophoretic mobilities of the enzymes. The molecular weight of the beta-galactosidase is about 4.2 X 10(5) and that of invertase is about 8.6 X 10(4). The beta-galactosidase has a Km for lactose of about 6 mM and a pH optimum between pH 6.0 and 6.5. The major invertase component has a Km for sucrose of about 71 mM and a pH optimum between pH 5.8 and 6.3.
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PMID:Identification, separation, and preliminary characterization of invertase and beta-galactosidase in Actinomyces viscosus. 1 74

Seven subjects were fed a 3,000 kcal defined formula diet daily for 19 days. Except for one 5-day period, 50% of the total caloric intake was provided as either oral or intravenous glucose. The study was divided into four periods as follows: period I lasted 5 days and provided 50% of calories as glucose; period II lasted 5 days and provided no carbohydrate (70% fat and 30% protein); period III lasted 4 days and provided 50% of calories as intravenous glucose and 50% of calories as oral fat plus protein; period IV lasted 5 days and provided 50% of calories as oral glucose. Intestinal biopsy specimens were taken on days 3 and 5 of each period, except period III when biopsies were done only on day 4. No change in intestinal morphology occurred during the study. The carbohydrate-free diet caused the alpha-glucosidase (maltase and sucrase) activities to decrease significantly from that seen with the glucose diet. Sucrase decreased from 14.4 +/- 1.0 to 7.1 +/- 0.9 mumoles/min per g tissue and maltase decreased from 56.1 +/- 3.4 to 30.0 +/- 2.1 mumoles/min per g tissue. Glycolytic enzyme activities decreased during the carbohydrate-free period (pyruvate kinase decreased from 236 +/- 12 to 78 +/- 8, fructose 1-phosphate aldolase decreased from 147 +/- 6 to 53 +/- 4, fructose-1,6-diphosphate aldolase decreased from 151 +/- 8 to 55 +/- 3, and hexokinase decreased from 21 +/- 3 to 7 +/- 1 nmoles/min per mg protein, respectively). Intravenous glucose caused no change in disaccharidase activities. The enzyme activities during periods I and IV were identical and significantly higher than during period II with the exception of fructose-1,6-diphosphatase which increased during period II as compared with periods I and IV. These findings provide an explanation for the transient period of decreased tolerance to dietary sugars when patients are weaned from total parenteral feedings to enteral feedings.
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PMID:Comparison of the adaptive changes in disaccharidase, glycolytic enzyme and fructosediphosphatase activities after intravenous and oral glucose in normal men. 17 Aug 20

In the genus Schizosaccharomyces intracellular osidases and nitrite and nitrate reductases are revealed; particularly all the species possessing invertase, alpha-glucosidase and alpha-galactosidase. These characters underline the homogeneity on the genus. On the basis of osidases, nitrite and nitrate reductases results, 2 groups can be distinguished in this genus.
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PMID:[Study of intracellular enzymes in the genus Schizosaccharomyces. Sistematic implications]. 19 42

Saccharomyces cerevisiae -136ts (Hutchison, H.T., Hartwell, L.H. and McLaughlin, C.S. (1969) J. Bacteriol. 99, 807-814) incubated in the presence of maltose at 23 degrees C (permissive temperature) synthesized the RNA messengers which codify derepressed invertase (an external mannoprotein) and induced alpha-glucosidase (a non-glycosylated internal enzyme). The enzymes were not synthesized if the mutant was transferred to the maltose-containing medium at the moment of incubation at 37 degrees C indicating that the cells had no pools of the specific RNA messengers and that transcription of the DNA was a prerequisite to enzyme synthesis. Cycloheximide inhibited syntheses of the enzymes both at 37 and at 23 degrees C suggesting that the enzymic activities were the result of "de novo" synthesis of the proteins and did not result from the activation of proenzymes. In derepressed cells the number of invertase mRNA molecules is probably larger than that actually being translated. The half-life of the derepressed invertase mRNA was calculated from the moment that the molecules of RNA messenger were limiting the enzyme synthesis and a value of 30-35 min was estimated. The value found for the basal (repression independent) invertase mRNA was of 45-50 min. The half-life of alpha-glucosidase mRNA was computed following the mathematical procedure described in the Appendix, and a value of 23 min was obtained. These results are consistent with the existence of relatively long-lived RNA messengers involved in the synthesis of extracellular macromolecules.
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PMID:Invertase messenger ribonucleic acid in Saccharomyces cerevisiae. Kinetics of formation and decay. 32 19

Brush border membrane bound disaccharidases (sucrase and maltase) and lysosomal enzyme (alpha-glucosidase, beta-D-fucosidase and N-acetyl-beta-glucosaminidase) activities awere studied in amniotic fluid (AF). The above enzymes except N-acetyl-beta-glucosaminidase showed a decrease in activity with gestational age beginning at about the 19th week. The activities of sucrase and maltase correlate with the morphological maturation of fetal intestinal mucosa. The distribution of disaccharidases and lysosomal alpha-glucosidase in AF and intestinal mucosa showed different patterns suggesting that these enzymes originate in diverse fetal tissues.
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PMID:Disaccharidase and lysosomal enzyme activities in amniotic fluid, intestinal mucosa and meconium. Correlation between morphology and disaccharidase activities in human fetal small intestine. 34 69

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

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 roles of extracellular and intracellular mechanisms in the degradation of brush border proteins have been investigated by studying the small intestinal mucosa of dogs with naturally occurring exocrine pancreatic insufficiency. Peroral jejunal biopsies were homogenised and the organelles separated by isopycnic centrifugation on continuous sucrose density gradients. The distributions of marker enzymes for the principal subcellular organelles were determined in the gradients and related to the specific activities in the homogenates. There were increased activities of the brush border carbohydrases zinc-resistant alpha-glucosidase, maltase and sucrase in the pancreatic insufficient animals, but no change in lactase activity. The activity of gamma-glutamyl transferase was also higher in the affected group; the activities of two other brush border enzymes, alkaline phosphatase and leucyl-beta-naphthylamidase, however, were unaltered. These findings with an increase in the modal density of the brush border from 1.20 to 1.22 are consistent with an enhanced glycoprotein content of the microvillus membrane. There were also rises in the activities of lysosomal enzymes. N-Acetyl-beta-glucosaminidase activity was increased in the soluble fractions and the percentage latent enzyme activity was reduced, findings indicative of an increased fragility of the lysosomal membrane. There were no marked alterations in the activities or density gradient distributions of marker enzymes for the other organelles, stressing the specificity of the changes in the brush borders and lysosomes. These findings are compatible with the degradation of certain exposed brush border proteins by pancreatic proteases and suggest that when this is defective, intracellular degradative mechanisms may be stimulated.
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PMID:Biochemical changes in the jejunal mucosa of dogs with naturally occurring exocrine pancreatic insufficiency. 48 65

Sucrase-isomaltase complex and its functional subunits have been identified in homogenates of human small intestinal mucosa by use of Sephadex G-200 (superfine) chromatography aided by affinity of the isomaltase moiety for the dextran gel. The isomaltase subunit binds strongly to the gel at 4 degrees, and is eluted only after 2 column volumes; earlier recovery as a sharp peak can be achieved by raising column temperature to 37 degrees after elution of other proteins. Bio-Gel P-300 chromatography, density gradient, and equilibrium centrifugation demonstrated that the sucrase subunit (Stokes radius = 45 A, frictional ratio = 1.32, s20,w = 6.9, MW = 130,000) and the isomaltase subunit (Stokes radius = 45 A, frictional ratio = 1.30, s20,w = 6.6, MW = 120,000) are similar but unequal in size. The sucrase-isomaltase complex (Stokes radius = 70 A, frictional ratio = 1.61, s20,w = 9.8, MW = 280,000), appears to be an elongated hybrid molecule that is less symmetrical than either of itt subunits. Apparent Km and pH activity curves were indistinguishable for each enzyme whether present in the hybrid or in the free state. The sucrase-isomaltase complex, accounting for approximately 90 percent of native intestinal sucrase and isomaltase activities, was isolated and cleaved by 0.01 M beta-mercaptoethanol/6 M urea treatment into active sucrase and isomaltase subunits having biochemical characteristics identical with those of the free native moieties. Sodium dodecyl sulfate acrylamide gell electrophoresis of the complex also produced subunits having molecular weights very close to those for the active free sucrase and isomaltase moieties, indicating that each alpha-glucosidase appears to consist of a single polypeptide chain. Immunization of rabbits with pure sucrase-isomaltase complex yielded a monospecific precipitating antibody that reacted with the hybrid and the sucrase subunit, but had minimal affinity for the isomaltase subunit, providing further evidence that the sucrase-isomaltase molecule is a hybrid consisting of two distinct alpha-glucosidases.
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PMID:Human intestinal sucrase-isomaltase. Identification of free sucrase and isomaltase and cleavage of the hybrid into active distinct subunits. 80 75


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