共查询到15条相似文献,搜索用时 15 毫秒
1.
R. P. Tengerdy J. E. Johnson J. Holló J. Tóth 《Applied biochemistry and biotechnology》1981,6(1):3-13
Pseudomonas fluorescens, immobilized on soft polyvinyl chloride granules containing up to 35% softeners as carbon source, was used for simultaneous
removal of nitrate and heavy metals. In typical continuous column operation, a 100 mg/L nitrate input solution was reduced
to a 20 mg/L output at a feeding rate of 1500 mL/h, with a capacity of 14 kg/day/m3, and with an efficiency of 79%. In the same column, Pb(NO3)2 concentration was reduced from 1.0 to 0.05−0.1 mg/L and ZnSO4 concentration was reduced from 10 to 5 mg/L.Pseudomonas aeruginosa immobilized on an O2 plasma-treated melt blown polypropylene web was used for removing 95% of a 1.7 nCi PuCl4 activity from a nuclear plant waste water in a batch operation. 相似文献
2.
Frycák P Zdráhal Z Ulrichová J Wiegrebe W Lemr K 《Journal of mass spectrometry : JMS》2005,40(10):1309-1318
Fumaric acid esters, namely dimethylfumarate, have been used for the treatment of psoriasis for many years. Still, their mode of action is not fully clear. Because addition of nucleophiles to the double bonds of fumarates can occur (Michael analogous addition), a study of the interaction of fumarates with cysteine and cysteine-containing peptides possessing nucleophilic sulfhydryl group was carried out. Experiments were performed in aqueous medium at pH 7.4 and at 37 degrees C to simulate physiological conditions. It was proven by mass spectrometric measurements using an ion-trap and time-of-flight instrument that a covalent bond can form between fumarates and the sulfhydryl group of cysteine or cysteinyl residues in peptides. Structures of the interaction products were elucidated by multistage mass spectrometry applying collision-induced dissociation. Higher reactivity of dimethylfumarate in comparison to monomethylfumarate and fumaric acid was observed. 相似文献
3.
Emulsion copolymerization of styrene and a cationic monomer vinylbenzyl-isothiouronium chloride (VBIC) with initiation by 2,2 azobis(2-amidinopropane)-dihydrochloride (V-50) gave monodisperse latex particles. After post-stabilization with cationic or non-ionic surfactants, the colloids were diluted in basic buffers with concomitant deprotection of the sulfhydryl groups. Therefore, coupling reactions on the latex beads were possible. Coupling conditions were determined with Ellman's reagent.14C iodoacetamide and anti C-reactive protein antibody Fab fragments were immobilized and finally, the immunological activity of the sensitized latex was assessed. 相似文献
4.
Gabriele K. Wienhausen Larry J. Kricka John E. Hinkley Marlene DeLuca 《Applied biochemistry and biotechnology》1982,7(6):463-473
NADH : FMN oxidoreductase and bacterial luciferase have been efficiently coimmobilized onto Sepharose 4B. This luminescent
immobilized enzyme system can be used to assay NADH. The assay is rapid and sensitive with a lower limit of detection of 0.2
pmol/assay tube. The intra-assay precision was 3.5% at 2 × 10-5
M and 5.8% at 2 × 10-6
M NADH. Light intensity was proportional to NADH concentration from 0.2 to 1000 pmol. Added serum and certain dehydrogenases
were found to be inhibitory; however, inhibition could be eliminated by a combination of heat treatment and dilution.
Firefly luciferase has also been immobilized onto both Sepharose 4B and CL 6B. The detection limit for ATP using this immobilized
enzyme was 0.2 pmol and the assay was linear from 0.2 to 2000 pmol. The intra-assay precision was 4.8% at 2 × 10-4
M and 3.2% at 1 × 10-5
M ATP.
The immobilized enzymes remained fully active when rapidly frozen in the presence of glycerol and DTT. Such preparations could
be stored for at least two months with no loss of activity. A variety of different compounds were used to block any remaining
reactive groups on the Sepharose following immobilization of the enzymes. Glycine, 2-aminoethanol, and ethylenediamine were
examined. The preparations where ethylenediamine was used as a blocking agent exhibited better activity and stability than
the others. 相似文献
5.
6.
Protein A-Sepharose CL-4B was used as a solid phase for antibodies in the radioimmunoassay of progesterone and estriol. The
method was fast and easily standardizable. Immobilized antibodies had the same binding capacity as free antibodies and gave
good correlation curves (r = 0.996 for progesterone andr = 0.989 for estriol). Sensitivity was 12.5 pg/tube for progesterone and 8.0 pg/tube for estriol. Comparison of progesterone
radioimmunoassay with chemically immobilized antibody onto Sepharose CL-4B was also carried out. 相似文献
7.
8.
2-Amino-4-chloro-s-triazine, a derivative of DEAE-cellulose, and acrolein/styrene copolymer were used as supports for the
immobilization of glucose oxidase and catalase after being modified with diaminohexane followed by glutaraldehyde. Immobilization
was carried out with optimum glucose oxidase-catalase ratios. The activity variations of the immobilized dual-enzyme systems
were investigated in relation to pH and temperature. Time-dependent gluconic acid production resulting from the oxidation
of glucose was monitored in a recycling fluid-bed reactor. The deactivation rates of glucose oxidase and catalase were investigated
according to the first-order reaction kinetics depending on the presence of the intermediate product H2O2. 相似文献
9.
ImmobilizedZoogloea and zooglan in calcium alginate-silica matrix was shown to have a high adsorption capacity for Cu and Cd ions. Our results
showed that Cu-ion uptake in the presence of Ca and Mg ions can be enhanced using immobilizedZoogloea and zooglan. Heavy metal ion adsorption efficiency decreased in the following order: Cu > Cd > Zn > Cr. The adsorbed metal
ions were desorbed completely using sulfuric acid. ImmobilizedZoogloea and zooglan which was repetitively regenerated adsorbed heavy metal ions without a loss of adsorption capacity. 相似文献
10.
S. C. F. Robison 《Chromatographia》1979,12(7):439-442
Summary A rapid method is described for the quantitative determination of aromatic-type groups in gas oil petroleum fractions. The method involves separation by high-performance liquid chromatography followed by detection with a differential refractometer, whose response to aromatic-type groups is more predictable than an ultra violet absorbance detector. A primary standard is used for calibration, and the precision and accuracy of the method have been investigated and are discussed. 相似文献
11.
It has been found that immobilized cells ofC. pasteurianum possessing hydrogenase activity efficiently catalyze reversible reduction of concentrated (up to 0.5M) solutions of methyl
viologen with H2. A 0.5M aqueous solution of methyl viologen dissolves 240 times as much H2 as pure water under the same pressure of hydrogen. The experimentally obtained levels of methyl viologen reduction and H2 evolution are in satisfactory agreement with theoretical calculations. The potential of concentrated solutions of methyl
viologen containing immobilized hydrogenase as a H2 storage medium is discussed. 相似文献
12.
Alkaline phosphatase, APase, (EC 3.1.31) from calf intestine, after shifting the equilibrium by effector molecules towards
the dimeric form of the enzyme, was coupled (ratio 1:2, protein: copolymer) to a copolymer of ethylene and maleic anhydride,
EMA. The water-soluble APase-EMA was separated from APase and the unbound EMA by DEAE-cellulose ion exchange chromatography.
The specific activity of the APase-EMA, compared to APase, increased 26-fold at pH 7.1 and 10-fold at pH 8.6. The pH optimum
of APase-EMA was shifted down from pH 9.5 (native APase) to 8.6. This change could be interpreted in terms of polyelectrolyte
theory. APase-EMA retained 50–70% of its optimum activity in the pH range 7–8, while APase retained only 5–15% of its optimum
activity within the same pH range. Its isoelectric point, pI, was 4.2 (APase 6.0) and it migrated on polyacrylamide gel electrophoresis
in a single band, anodic movement twice as fast as APase. Parallel with the kinetic measurements, the reactive-enzyme sedimentation
method was used to measure S20,w values. S20,w values obtained for APase-EMA, activated APase, and APase dialyzed against wafer were 6.56S, 6.46S, and 5.17S, respectively.
Molecular weights, Mr, were determined by equilibrium sedimentation: the values obtained were 180,000, 160,000, and 84,500. Mr values of APase-EMA and APase (native) estimated by Sepharose-4B gel filtrations were essentially the same. The above-mentioned
values remained unchanged for APase-EMA after intensive dialysis against water, whereas for the activated APase, separation
from the effector molecules caused the equilibrium to shift back to the monomeric, very slightly active enzyme with concomitant
changes of S20,w to 5.15 and Mr to 82,000. 相似文献
13.
O. A. Linchenko I. Yu. Krasnova P. V. Petrovskii I. A. Garbuzova V. N. Khrustalev Yu. G. Gololobov 《Russian Chemical Bulletin》2007,56(8):1671-1674
The reactions of carbanions of diethyl phenyl and 4-nitrophenylmalonates with phenyl isocyanate occur with 1,3-C→N migration
of the ethoxycarbonyl group to form the corresponding adducts. The introduction of NO2 groups into the benzene ring of arylmalonates inhibits the reaction.
Dedicated to Academician V. A. Tartakovsky on the occasion of his 75th birthday.
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 1608–1610, August, 2007. 相似文献
14.
Permanent need to understand nature, structure and properties of humic substances influences also separation methods that are in a wide scope used for fractionation, characterization and analysis of humic substances (HS). At the first glance techniques based on size-exclusion phenomena are the most useful and utilized for relating elution data to the molecular mass distribution of HS, however, with some limitations and exceptions, respectively, in the structural investigation of HS. The second most abundant separation mechanism is reversed-phase based on weak hydrophobic interactions beneficially combined with the step gradients inducing distinct features in rather featureless analytical signal of HS. Relatively great effort is invested to the developments of immobilized-metal affinity chromatography mimicking chelate-forming properties of HS as ligands in the environment. Surprisingly, relatively less attention is given to the ion-ion interactions based ion-exchange chromatography of HS. Chromatographic separation methods play also an important role in the examination of interactions of HS with pesticides. They allow us to determine binding constants and the other data necessary to predict the mobility of chemical pollutants in the environment. HS is frequently adversely acting in analytical procedures as interfering substance, so more detailed information is desired on manifestation of its numerous properties in analytical procedures. The article topic is covered by the review emphasizing advances in the field done in the period of last 10 years from 2000 till 2010. 相似文献
15.
A method is presented for the simultaneous determination of a wide range of carboxylic acids and phenols in water. Extractive alkylation is used with the tetrabutylammonium ion as counter ion and pentafluorobenzylbromide as alkylating agent. Extracts are analyzed by glass capillary gas chromatography and electron capture detection. Using one ml of water sample, the detection limit lies in the range of 1–10 μg/l. Application has been made to the analysis of steam condensate and domestic sewage effluent. 相似文献