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)

Hydroponically cultivated barley plants were exposed to nitrogen (N)-deficiency followed by N-resupply. Metabolic and genetic regulation of fructan accumulation in the leaves were investigated. Fructan accumulated in barley leaves under N-deficiency was mobilized during N-resupply. The enhanced total activity of fructan-synthesizing enzymes, sucrose:sucrose 1-fructosyltransferase (EC 2.4.1.99) and sucrose:fructan 6-fructosyltransferase (6-SFT; EC 2.4. 1.10) caused by N-deficiency decreased with the mobilization of fructan during N-resupply. The activity of the barley fructan-degrading enzyme, fructan exohydrolyase (EC 3.2.1.80) was less affected by the N status. The low level of foliar soluble acid invertase activity under N-deficiency conditions was maintained during the commencement of N-resupply but increased subsequently. Further analyses by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, western blot and northern blot demonstrated that the fructan accumulation and the total activity of fructan-synthesizing enzymes correlated with the 6-SFT mRNA level. We suggest that the changes in fructan levels under N stress are intimately connected with the regulation of fructan synthetic rate which is mostly controlled by 6-SFT.
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PMID:Fructan accumulation induced by nitrogen deficiency in barley leaves correlates with the level of sucrose:fructan 6-fructosyltransferase mRNA. 1108 83

The main component of inulinase was purified from fermentation broth of Aspergillus niger 319 to homogeneity by using ammonium sulfate fraction, ion-exchange chromatography on DEAE-cellulose column and Sephadex G-100 gel filtration. The specific activity was as 67 folds at the fermentation broth, and the yield was 25.5%. The inulinase, containing 13.92% of carbohydrate, was a monomer protein with a molecular weight of 28,000 Dalton; and its isoelectric point was pH 5.4. The optimal pH and temperature of the inulinase was pH 5.0 and 60 degrees C, respectively. The enzyme was strongly inhibited by heavy metal ions of Hg2+, Pb2+ and Cu2+. The optimal substrate for the enzyme was inulin and the product was only fructose, but it also had invertase activity with the I/S of 0.348. The Km and Vm of the inulinase was 6.25 mmol/L and 67.11 mumol.mg-1.min-1, respectively.
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PMID:[Purification and properties of inulinase from Aspergillus niger]. 1118 61

The ability of Actinomyces naeslundii to convert sucrose to extracellular homopolymers of fructose and to catabolize these types of polymers is suspected to be a virulence trait that contributes to the initiation and progression of dental caries and periodontal diseases. Previously, we reported on the isolation and characterization of the gene, ftf, encoding the fructosyltransferase (FTF) of A. naeslundii WVU45. Allelic exchange mutagenesis was used to inactivate ftf, revealing that FTF-deficient stains were completely devoid of the capacity to produce levan-type (beta2,6-linked) polysaccharides. A polyclonal antibody was raised to a histidine-tagged, purified A. naeslundii FTF, and the antibody was used to localize the enzyme in the supernatant fluid. A sensitive technique was developed to detect levan formation by proteins that had been separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and the method was used to confirm that the levan-synthesizing activity of A. naeslundii existed predominantly in a cell-free form, that a small amount of the activity was cell associated, and that the ftf mutant was unable to produce levans. By using the nucleotide sequence of the levanase gene of a genospecies 2 A. naeslundii, formerly Actinomyces viscosus, a portion of a homologue of this gene (levJ) was amplified by PCR and inserted into a suicide vector, and the resulting construct was used to inactivate the levJ gene in the genospecies 1 strain WVU45. A variety of physiologic and biochemical studies were performed on the wild-type and LevJ-deficient strains to demonstrate that (i) this enzyme was the dominant levanase and sucrase of A. naeslundii; (ii) that LevJ was inducible by growth in sucrose; (iii) that the LevJ activity was found predominantly (>90%) in a cell-associated form; and (iv) that there was a second, fructose-inducible fructan hydrolase activity produced by these strains. The data provide the first detailed molecular analysis of fructan production and catabolism in this abundant and important oral bacterium.
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PMID:Roles of fructosyltransferase and levanase-sucrase of Actinomyces naeslundii in fructan and sucrose metabolism. 1150 Apr 9

We isolated spontaneous mutants from Saccharomyces cerevisiae (baker's yeast V1) that were resistant to 2-deoxy-D-glucose and had improved fermentative capacity on sweet doughs. Three mutants could grow at the same rate as the wild type in minimal SD medium (0.17% Difco yeast nitrogen base without amino acids and ammonium sulfate, 0.5% ammonium sulfate, 2% glucose) and had stable elevated levels of maltase and/or invertase under repression conditions but lower levels in maltose-supplemented media. Two of the mutants also had high levels of phosphatase active on 2-deoxy-D-glucose-6-phosphate. Dough fermentation (CO2 liberation) by two of the mutants was faster and/or produced higher final volumes than that by the wild type, both under laboratory and industrial conditions, when the doughs were supplemented with glucose or sucrose. However, the three mutants were slower when fermenting plain doughs. Fermented sweet bakery products obtained with these mutants were of better quality than those produced by the wild type, with regard to their texture and their organoleptic properties.
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PMID:Improved properties of baker's yeast mutants resistant to 2-deoxy-D-glucose. 1152 34

A most potent alpha-glucosidase inhibitor named salacinol has been isolated from an antidiabetic Ayurvedic traditional medicine, Salacia reticulata WIGHT, through bioassay-guided separation. The absolute stereostructure of salacinol was determined on the basis of chemical and physicochemical evidence, which included the alkaline degradation of salacinol to 1-deoxy-4-thio-D-arabinofuranose and the X-ray crystallographic analysis, to be the unique spiro-like configuration of the inner salt comprised of 1-deoxy-4-thio-D-arabinofuranosyl sulfonium cation and 1'-deoxy-D-erythrosyl-3'-sulfate anion. Salacinol showed potent inhibitory activities on several alpha-glucosidases, such as maltase, sucrase, and isomaltase, and the inhibitory effects on serum glucose levels in maltose- and sucrose-loaded rats (in vivo) were found to be more potent than that of acarbose, a commercial alpha-glucosidase inhibitor.
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PMID:Absolute stereostructure of potent alpha-glucosidase inhibitor, Salacinol, with unique thiosugar sulfonium sulfate inner salt structure from Salacia reticulata. 1188 16

An invertase (beta-D-fructofuranoside fructohydrolase, EC 3.2.1.26) from Rhodotorula glutinis was purified by ammonium sulfate fractionation, gel filtration and anion exchange chromatography. Invertase molecular weight was estimated to be 100 kDa by analytical gel filtration and 47 kDa by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). Molecular mass determinations indicated that the native enzyme exists as a homodimer. It is a glycoprotein that contains 19% carbohydrate. The enzyme attacks beta-D-fructofuranoside (raffinose, stachyose and sucrose) from the fructose end. It has a K(m) of 0.227 M and a V(max) of 0.096 micromol/min with sucrose as a substrate. Invertase activity is stable between pH 2.6 and 5.5 for 30 min, maximum activity being observed at pH 4.5. The activation energy was 6520 cal/mol. The enzyme is stable between 20 and 60 degrees C. Mg(2+) and Ca(2+) ions stimulated invertase activity 3-fold, while Fe(2+), K(+), Co(2+), Na(+) and Cu(2+) increased activity about 2-fold. The transfructosylation reaction could not be observed. This enzyme is of particular interest since it appears to have a high hydrolytic activity in 1 M sucrose solution. This fact would make the enzymatic hydrolysis process economically efficient for syrup production using by-products with high salt and sugar contents such as sugar cane molasses.
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PMID:Invertase from a strain of Rhodotorula glutinis. 1242 80

The extracellular cellobiase (EC 3.2.1.21) of Termitomyces clypeatus separated in two protein fractions when culture filtrate or ammonium sulfate precipitated proteins were chromatographed on BioGel P-200 column. During purification of cellobiase (CBS) from the lower molar mass (LMM) protein fraction, the enzyme behaved like a low molecular weight multimeric protein. The purified enzyme gave a single 56 kDa band in SDS-PAGE but ladderlike bands (14, 28, 42, and 56 kDa) on denaturation by reducing-SDS and urea. The protein, however, dissociated on dilution and protomeric (14 kDa) and multimeric forms (28 and 60 kDa) were eluted separately during HPGPLC. Specific activity of CBS gradually decreased as the molar mass of the enzyme was lowered in different eluted peaks. Protein present in all CBS pool fractions had the same amino acid composition and all displayed the same, single protein peak in reverse-phase HPLC and 56 kDa band in SDS-PAGE. Thus, T. clypeatus CBS was a multimeric 14 kDa protein that was optimally active as a tetramer. CBS purified from the higher molar mass fraction (HMM) as a SDS-PAGE homogeneous 110-kDa protein did not dissociate on dilution or by SDS-urea. The purified protein was a protein aggregate as CBS consistently contained 20 +/- 5% sucrase (SUC) Units in the preparation. The aggregate resolved during reverse-phase chromatography on a C(4) column, and an additional protein peak other than CBS was detected. The aggregated CBS had a higher temperature optimum and was more stable toward thermal and chemical denaturations than SUC-free CBS. Increase of stability and catalytic activity of CBS by aggregation with SUC was much higher than those by the multimerization of CBS itself. All of these observations for the first time suggested that the heterologous protein-protein aggregation, observed for a long time for fungal enzymes, might have a significant role in modulating physicochemical properties of the extracellular enzyme.
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PMID:Stabilization and improvement of catalytic activity of a low molar mass cellobiase by cellobiase-sucrase aggregation in the culture filtrate of Termitomyces clypeatus. 1246 58

This report represents the conclusions of a Joint FAO/WHO Expert Committee convened to evaluate the safety of various food additives and contaminants, with a view to recommending Acceptable Daily Intakes (ADIs) and tolerable intakes, respectively, and to prepare specifications for the identity and purity of food additives. The first part of the report contains a general discussion of the principles governing the toxicological evaluation of food additives (including flavouring agents) and contaminants, assessments of intake, and the establishment and revision of specifications for food additives. A summary follows of the Committee's evaluations of toxicological and intake data on various specific food additives (diacetyltartaric and fatty acid esters of glycerol, quillaia extracts, invertase from Saccharomyces cerevisiae, beta-carotene from Blakeslea trispora, curcumin, phosphates, diphosphates and polyphosphates, hydrogenated poly-1-decene, natamycin, D-tagatose, carrageenan, processed Eucheuma seaweed, curdlan, acetylated oxidized starch, alpha-cyclodextrin and sodium sulfate), flavouring agents and contaminants (3-chloro-1,2-propanediol, 1,3-dichloro-2-propanol, and a large number of polychlorinated dibenzodioxins, polychlorinated dibenzofurans and coplanar polychlorinated biphenyls). Annexed to the report are tables summarizing the Committee's recommendations for ADIs of the food additives and tolerable intakes of the contaminants considered, changes in the status of specifications of these food additives and specific flavouring agents, and further information required or desired.
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PMID:Evaluation of certain food additives and contaminants. 1256 44

Immobilization of invertase in conducting copolymer matrices of 3-methylthienyl methacrylate with pyrrole and thiophene was achieved by constant potential electrolysis using sodium dodecyl sulfate (SDS) as the supporting electrolyte. Polythiophene (PTh) was also used in entrapment process for comparison. Kinetic parameters, Michaelis-Menten constant, K(m), and the maximum reaction rate, V(max), were investigated. Operational stability and temperature optimization of the enzyme electrodes were also examined.
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PMID:Immobilization of invertase in conducting copolymers of 3-methylthienyl methacrylate. 1269 16

The possibility of screening the mercury(II) content in real environmental samples based on inhibition of the activity of dissolved invertase has been examined. The extent of inhibition was measured with an amperometric glucose biosensor with glucose oxidase immobilized on a membrane. Data concerning the stability and reproducibility of measurements are provided. The effects of heavy metals on the inhibition of invertase, together with that of common anions such as chloride, nitrate and sulfate are reported. The determination of mercury using this procedure has been carried out in samples of natural and waste water samples of various origins already analyzed by ICP-AES, by spiking ppb levels of mercury(II). Differences in the inhibiting effect of the samples and in the recoveries were found and are discussed.
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PMID:Limitations in the analytical use of invertase inhibition for the screening of trace mercury content in environmental samples. 1522 7


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