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 utilization by Escherichia coli K12 of raffinose as sole carbon source depends on a new raffinose transport system, an invertase and an alpha-galactosidase specified by the Raf-plasmid D1021. The alpha-galactosidase was purified to homogeneity from a mutant strain with constitutive synthesis of the enzyme. alpha-Galactosidase hydrolyzes p-nitrophenyl-alpha-D-galactoside (Km 0.14 mM), methyl-alpha-D-galactoside (Km 30mM), melibiose (Km 3.2 mM) and raffinose (Km 60 mM). The enzymatic activity is strongly inhibited by Ag+, p-chloromercuriphenyl sulfonic acid and, to a lesser extent, by iodoacetamide. Isoelectric focusing indicates the existence of one form of alpha-galactosidase with an isoelectric point of 5.1. The purified enzyme has an sw,20 value of 11.7 +/- 0.3S and a molecular weight of 329000 +/- 4000; this value is not reduced at high dilutions. When examined by dodecylsulphate gel electrophoresis, purified alpha-galactosidase yields a single subunit band of molecular weight 82000 suggesting that the intact enzyme consists of four subunits. Amino acid analysis indicates the presence of approximately 712 amino acid residues per quarter molecule including 8 half-cystine residues. No carbohydrate moiety has been detected. High resolution electron micrographs and Markham rotation of alpha-galactosidase show enzyme molecules of approximately 11 x 11 nm containing four globular subunits in a tetragonal arrangement. The plasmid-coded alpha-galactosidase differs from the homologous E. coli enzyme by substrate affinities, cofactor requirements, stability and toluene resistance. It can, therefore, be used as a marker enzyme suitable for the detection in vivo of Raf-plasmids.
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PMID:Raffinose metabolism in Escherichia coli K12. Purification and properties of a new alpha-galactosidase specified by a transmissible plasmid. 78 27

Cysteine or dithiothreitol enhances the rate of autolysis in toluene-treated yeast. p-Toluenethiol alone is even more effective and is recommended for the isolation of beta-fructofuranosidase. This suggests a more general application of p-toluenethiol in the isolation of enzymes from yeast.
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PMID:p-Toluenethiol as an initiator of autolysis in bakers' yeast. 505 57

Cells of the fission yeast Schizosaccharomyces pombe were permeabilized by treatment with toluene-ethanol. The permeabilized cells lost the bulk of the internal trehalose pool while most of the alkaline phosphatase, invertase, alpha-glucosidase, or neutral trehalase activities located inside the cells remained unaffected. This system was used as an in situ assay to determine the involvement of trehalose in enzyme protection during thermal treatments. The addition of trehalose to suspensions of permeabilized cells resulted in a sugar-dependent thermoprotection of the internal marker enzymes. This approach demonstrates that in whole cells of the fission yeast trehalose plays a physiological role as a protective molecule against thermal denaturation of cellular enzymes.
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PMID:Increased thermal stability of the enzyme content in permeabilized whole cells from the fission yeast Schizosaccharomyces pombe by exogenous trehalose and other compounds. 859 Apr 7

Baker's yeast invertase was found to catalyse transfructosylation reactions in aqueous and anhydrous organic media with sucrose as a substrate, leading to the formation of five intermediate fructans in addition to the release of D-glucose (D-Glc)and D-fructose (D-Fru). All the reaction products were separated and quantitatively estimated using high performance anion exchange-pulsed amperometric detection equipment. The unknown products were subsequently identified by linkage analysis as beta-D-Fru-(2 --> 1)-beta-D-Fru-(2 --> 1)- alpha-D-glucopyranoside (1-kestose), beta-D-Fru- (2 --> 6)-alpha-D-glucopyranoside (6-beta-fructofuranosylglucose), beta-D-Fru-(2 -->1) -beta-D-fructofuranoside (inulobiose), beta-D-Fru-(2 --> 6)-beta-D-Fru-(2 --> 1)-alpha-D-glucopyranoside (6-kestose) and beta-D-Fru-(2 --> 6)-alpha-D-Glc-(1 --> 2)-beta-D-fructofuranoside (neokestose); and this last was eluted together with a disaccharide. The time-course of sucrose hydrolysis via fructan production in 2 ml of a 50 mM sodium acetate buffer (pH 4.5) containing 0.2 M sucrose and 25 U of invertase was different from that in 2 ml of anhydrous toluene with 1.46 M sucrose and 1,000 U of invertase as a suspended powder. Under the latter experimental conditions, invertase was found to exhibit cyclic behaviour, where sucrose was degraded and subsequently synthesised. This observation has not yet been reported, as far as we know.
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PMID:Application of high performance anion exchange chromatography to study invertase-catalysed hydrolysis of sucrose and formation of intermediate fructan products. 1123 59

The attachment of enzymes to glass microfluidic channels has been achieved using a highly reactive poly(maleic anhydride-alt-alpha-olefin) (PMA)-based coating that is supplied to the microchannel in a toluene solution. The PMA reacts with 3-aminopropyltriethoxysilane groups linked to the glass surface to form a matrix that enables additional maleic anhydride groups to react with free amino groups on enzymes to give a mixed covalent-noncovalent immobilization support. Using a simple T-channel microfluidic design, with reaction channel dimensions of 200 microm wide (at the center), 15 microm deep, and 30 mm long giving a reaction volume of 90 nL, soybean peroxidase (SBP) was attached at an amount up to 0.6 microg/channel. SBP-catalyzed oxidation of p-cresol was performed in aqueous buffer (with 20% [v/v], dimethylformamide) containing H(2)O(2), with microfluidic transport enabled by electroosmotic flow (EOF). Michaelis-Menten kinetics were obtained with K(m) and V(max) values of 0.98 mM and 0.21 micromol H(2)O(2) converted/mg SBP per minute, respectively. These values are nearly identical to nonimmobilized SBP kinetics in aqueous-DMF solutions in 20-microL volumes in 384-well plates and 5-mL reaction volumes in 20-mL scintillation vials. These results indicate that SBP displays intrinsically native activity even in the immobilized form at the microscale, and further attests to the mild immobilization conditions afforded by PMA. Bienzymic and trienzymic reactions were also performed in the microfluidic biochip. Specifically, a combined Candida antarctica lipase B-SBP bienzymic system was used to convert tolyl acetate into poly(p-cresol), and an invertase-glucose oxidase SBP trienzymic system was used to take sucrose and generate H(2)O(2) for SBP-catalyzed synthesis of poly(p-cresol).
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PMID:Multienzyme catalysis in microfluidic biochips. 1274 Sep 29

A new biosensor for specific determination of sucrose was developed using an oxidoreductase of Zymomonas mobilis and invertase. Cells of Z. mobilis were permeabilized with toluene in order to utilize the enzymes of glucose-fructose oxidoreductase and gluconolactonase inside the intact cells. Permeabilized cells and invertase were coimmobilized in a gelatin membrane, and a whole cell enzyme electrode was constructed by fixing the membrane on a pH electrode. The production of hydrogen ion was detected using the biosensor-connected microcomputer, and the concentration of sucrose was determined by using both the initial rate and the steady-state methods. Optimum conditions for biosensor response were pH 6.2 and temperature 35 degrees C. The effect of interfering compounds on the electrode response was investigated, and the interference by various sugars was eliminated by determining sucrose concentration using the steady-state method. The biosensor developed is simple and reproducible, and the calibration curve for sucrose is linear up to 70 g/L.
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PMID:A new biosensor for specific determination of sucrose using an oxidoreductase of Zymomonas mobilis and invertase. 1860 Jul 54

Stabilisation of electrochemically deposited Prussian blue (PB) films on glassy carbon (GC) electrodes has been investigated and an enhancement in the stability of the PB films is reported if the electrodes are treated with tetrabutylammonium toluene-4-sulfonate (TTS) in the electrochemical activation step following the electrodeposition. A multi-enzyme PB based biosensor for sucrose detection was made in order to demonstrate that PB films can be coupled with an oxidase system. A tri-enzyme system, comprising glucose oxidase, mutarotase and invertase, was crosslinked with glutaraldehyde and bovine albumin serum on the PB modified glassy carbon electrode. The deposited PB operated as an electrocatalyst for electrochemical reduction of hydrogen peroxide, the final product of the enzyme reaction sequence. The electrochemical response was studied using flow injection analysis for the determination of sucrose, glucose and H(2)O(2). The optimal concentrations of the immobilisation mixture was standardised as 8U of glucose oxidase, 8U of mutarotase, 16U of invertase, 0.5% glutaraldehyde (0.025mul) and 0.5% BSA (0.025mg) in a final volume of 5mul applied at the electrode surface (0.066cm(2)). The biosensor exhibited a linear response for sucrose (4-800muM), glucose (2-800muM) and H(2)O(2) (1-800muM) and the detection limit was 4.5, 1.5 and 0.5muM for sucrose, glucose and H(2)O(2), respectively. The sample throughput was ca. 60 samples h(-1). An increase in the operational and storage stability of the sucrose biosensor was also noted when the PB modified electrodes were conditioned in phosphate buffer containing 0.05M TTS during the preparation of the PB films.
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PMID:Prussian blue modified glassy carbon electrodes-study on operational stability and its application as a sucrose biosensor. 1896 61

Inversion of sucrose by bakers' yeast follows the same course as inversion catalyzed by yeast invertase. Rate of inversion increases exponentially with temperature; the temperature characteristic in the Arrhenius equation is 10,700 below 13-17 degrees C., and 8,300 above that temperature. Temperature inactivation occurs above 40 degrees C. The effects of temperature upon rate of inversion were the same using Fleischmann's yeast cake, the same yeast killed with toluene, and a pure strain (G. M. No. 21062) of bakers' yeast. The last differed from the other two only in the fact that its critical temperature was 13 degrees C. as compared with 17 degrees C. for the others. The catalytic inversion is associated with enzyme activity inside the cell, not in the medium, and is independent of any vital processes inside the cell such as respiration and fermentation. Since invertase activity is the same inside the cell as it is after extraction, it appears possible to relate the temperature characteristics for physiological processes to the catalytic chemical systems which determine their rate. At least two enzymes are capable of inverting sucrose in the yeast cell. The familiar yeast invertase (micro = 10,700) is active below 13-17 degrees C. while a second enzyme (M = 8,300) plays the dominant role above that temperature.
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PMID:SUCROSE INVERSION BY BAKERS' YEAST AS A FUNCTION OF TEMPERATURE. 1987 76