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 production of dextransucrase from Leuconostoc mesenteroides NRRL B-512F was stimulated 2-fold by the addition of 0.005% of calcium chloride to the medium; levansucrase levels were unaffected. Dextransucrase was purified by concentration and dialysis of the culture supernatant with a Bio-Fiber 80 miniplant, and by treatment with dextranase followed by chromatography on Bio-Gel A-Fm. A 240-fold purification, with a specific activity of 53 U/mg, was obtained. Contaminating enzyme activities of levansucrase, invertase, dextranase, glucosidase, and sucrose phosphorylase were decreased to non-detectable levels. Poly(acrylamide)-gel electrophoresis of the purified enzyme showed only two protein bands, both of which had dextransucrase activity. These bands also gave a carbohydrate stain, indicating that the dextransucrase could be a glycoprotein. Acid hydrolysis, followed by paper chromatography, of the purified enzyme showed that the major carbohydrate was mannose. Concanavalin A completely removed dextransucrase activity from solution, confirming the mannoglycoprotein character of the enzyme. Dextransucrase activity was not altered by the addition of 0.008-4 mg/ml of dextran, but its storage stability was increased by the addition of 4 mg/ml of dextran. As previously shown by others, the activity of dextransucrase was decreased by EDTA, and was restored by the addition of calcium ions. Zinc, cadmium, lead, mercury, and copper ions were inhibitory to various degrees.
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PMID:Production, purification, and properties of dextransucrase from Leuconostoc mesenteroides NRRL B-512F. 10 66

Two kojibiose-type pseudo-disaccharides and a trisaccharide, containing a 5-amino-1,2,3,4-cyclopentanetetrol derivative or valienamine, linked by way of nitrogen bridges to the sugar residues, have been designed and synthesized as processing alpha-glucosidase I inhibitors. Synthesis of the pseudo-disaccharides was carried out starting from the coupling products of the sugar isothiocyanates and an aminocyclitol, respectively, by cyclization with mercury(II) oxide to the cyclic isoureas and subsequent deprotection. Pseudokojibiose was prepared in a poor yield by reaction of a protected valienamine and a sugar epoxide, followed by deprotection. Although the pseudooligosaccharides are all strong inhibitors of alpha-glucosidase (baker's yeast), they did not have any inhibitory potency against either sucrase isomaltase (rat intestine) or processing alpha-glucosidase (rat liver microsomes).
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PMID:Synthesis of alpha-glucosidase inhibitors: kojibiose-type pseudo-disaccharides and a related pseudotrisaccharide. 965 66

An enzymatic amperometric procedure for measurement of mercury(II) in pharmaceuticals, based on the inhibition of invertase and on a glucose electrode was studied. Analytical parameters for measurements in batch and flow injection analysis (FIA) have been optimised. Mercury(II) was detected in the 10-60 ppb range with RSD < or =2%. A sample throughput of 6 h(-1) for batch and 15 h(-1) for FIA was obtained. The total mercury(II) from thimerosal (thiomersal, sodium ethylmercurithiosalicylate) in eye-drop samples was measured with the amperometric procedure after oxidative cleavage treatment. Results for both batch and FIA procedures correlated well with atomic absorbtion spectroscopy (AAS) data.
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PMID:Flow injection analysis of mercury(II) in pharmaceuticals based on enzyme inhibition and biosensor detection. 1070 31

The determination of mercury(II) ions at the trace level by inhibition of the invertase enzyme-catalysed hydrolysis of sucrose into glucose and fructose coupled to electrochemical batch injection analysis was investigated using two approaches. In the first, the glucose produced was detected by injection of 100 microliters samples into the batch injection cell containing a platinum electrode modified by immobilised glucose oxidase. In the second, the glucose and fructose present in injected samples were oxidised directly at a copper-modified glassy carbon electrode. The experimental parameters were optimised and the degree of enzyme inhibition by mercury(II) ions under both conditions was measured. Mercury concentrations in the ng ml-1 range were determined by these two techniques with low sample and reagent consumption. Comparison is made between the two methods and perspectives as a screening test for field application are indicated.
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PMID:Determination of mercury(II) by invertase enzyme inhibition coupled with batch injection analysis. 1219 51

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

We are reporting fabrication and characterization of electrochemical sucrose biosensor using ultra-microelectrode (UME) for the detection of heavy metal ions (Hg(II), Ag(I), Pb(II) and Cd(II)). The working UME, with 25 microm diameter, was modified with invertase (INV, EC: 3.2.1.26) and glucose oxidase (GOD, EC: 1.1.3.4) entrapped in agarose-guar gum. The hydrophilic character of the agarose-guar gum composite matrix was checked by water contact angle measurement. The atomic force microscopy (AFM) images of the membranes showed proper confinement of both the enzymes during co-immobilization. The dynamic range for sucrose biosensor was achieved in the range of 1 x 10(-10) to 1 x 10(-7)M with lower detection limit 1 x 10(-10)M at pH 5.5 with 9 cycles of reuse. The spectrophotometric and electrochemical studies showed linear relationship between concentration of heavy metal ions and degree of inhibition of invertase. The toxicity sequence for invertase using both methods was observed as Hg(2+)>Pb(2+)>Ag(+)>Cd(2+). The dynamic linear range for mercury using electrochemical biosensor was observed in the range of 5 x 10(-10) to 12.5 x 10(-10)M for sucrose. The lower detection limit for the fabricated biosensor was found to be 5 x 10(-10)M. The reliability of the electrochemical biosensor was conformed by testing the spike samples and the results were comparable with the conventional photometric DNSA method.
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PMID:Invertase inhibition based electrochemical sensor for the detection of heavy metal ions in aqueous system: Application of ultra-microelectrode to enhance sucrose biosensor's sensitivity. 1866 98

Procedures are described for the accurate determination of silver (2-10 x 10(-7)M) and mercury(II) (2-10 x 10(-7)M) in the presence of each other and of most other metals. The methods are based on the inhibition by these metals of invertase catalysis of the hydrolysis of sucrose.
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PMID:Applications of enzyme-catalysed reactions in trace analysis--I. Determination of mercury and silver by their inhibition of invertase. 1896 Mar 61

Methods are described for the determination of cyanide (10(-8)-10(-5)M and sulphide (10(-7)-10(-5)M) based on the de-inhibitory effect of these ions on invertase inhibited by mercury(II) or by silver. Iodine (0.1-3 mug) may be determined by its inhibition of invertase.
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PMID:Applications of enzyme-catalysed reactions in trace analysis-II Determination of cyanide, sulphide, and iodine with invertase. 1896 Apr 55

This paper describes the utilization of the inhibition of beta-fructofuranosidase by Hg(II) during the hydrolysis of saccharose, for the determination of Hg(II) in waters and drinks. The mercury levels in the samples tested ranged from 100 to 270ng l .
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PMID:An enzyme-catalysed method for the determination of mercury traces in carbonated soft drinks, by the Hg(2+) inhibition of beta-fructofuranosidase. 1896 14

The electrochemical oxidation of mono- and disaccharides at various copper-modified electrodes is reported: glassy carbon modified at open circuit or by electrochemical deposition of copper, gold modified by electrochemical deposition, and at bulk copper electrodes. A comparative study of these four electrodes was made by linear sweep voltammetry and amperometry. The maximum oxidation peak separation between disaccharides and monosaccharides is about 200mV. After optimization, amperometric determination of monosaccharides was done at +0.30 versus Ag/AgCl in 0.15M NaOH at the copper-modified gold electrode. Using the developed method, the enzymatic activities of invertase and beta-galactosidase were determined through their reaction with sucrose and lactose, respectively. Validation was carried out by a spectrophotometric method based on 3,5-dinitrosalicylic acid, and it was shown that the proposed electrochemical method is more sensitive. The analytical utility of the copper-modified gold electrode was tested for the determination of organic mercury. Addition of phenylmercury standards to the invertase solution caused a decrease in the enzyme activity, and allowed the determination of phenylmercury in pharmaceutical samples. The concentration has been determined in the 10-55ngml(-1) range.
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PMID:Copper-modified gold electrode specific for monosaccharide detection Use in amperometric determination of phenylmercury based on invertase enzyme inhibition. 1896 85


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