Catalytic oxidations

Objective of the study: The general objective of this study is to produce catalysts of bimetallic oxides (Cu-Co), on porous materials (activated carbon, silica gel, MCM-41) to adsorb and oxidize VOCs, which is represented by toluene, a popular VOCs with particular properties of the BTEX group in many industrial factories, at low temperature.

144p armyofthedead 23-06-2021 22 2   Download

Research purpose: Using computational chemistry methods to study the mechanism of hydrogenation CO on the transition metal catalyst systems of Ni, Cu, Co, bimetallic catalysts NiCu, CoCu and catalytic systems bearing cluster on oxide carriers: MgO, Al2O3 and activated carbon (AC); compare and clarify the role of catalyst centers in single or bimetallic catalyst systems; clarifies the role of carriers (MgO, Al2O3 and AC) in the hydrogenation of CO.

27p thebadguys 08-06-2021 27 4   Download

Successfully synthesized nano – mixed oxide by different gelling agents; compared, selected the appropriate gelling agent; researched to evaluate the catalytic activity of mixed oxide nanoparticles formed with pollutants methyl orange (MO), methylene blue (MB). Successful dispersed mixed oxide nanoparticles on rGO; investigated catalytic activity of material systems on parathion, fenitrothion.

28p capheviahe26 25-01-2021 33 5   Download

Main contents of thesis: Introdution of fuel cell and studies on Pt catalysts and Pt alloy catalysts in PEMFC. Research on synthesis of catalytic materials Pt/C 20% wt. by electroless deposition method and evaluating to influence of experimental parameters such as pH, temperature... in the synthesis process on the properties of catalyst Pt / C 20%wt.

22p xacxuoc4321 09-07-2019 52 4   Download

Recovering useful hydrocarbons from sewage sludge using zirconia-supporting iron oxide catalysts was investigated. Zirconia has activity for decomposing water molecules to generate active oxygen and hydrogen species.

6p tuananhhumg 04-11-2013 37 2   Download

In petroleum industry, it is desirable to produce lighter hydrocarbons such as gasoline, kerosene and gas–oil from unused heavy oils. Thus we have developed zirconia-supporting iron oxide catalysts View the MathML source to decompose petroleum residual oil (atmospheric distilled residual oil) with steam.

6p tuananhhumg 04-11-2013 59 3   Download

To examine the role of the distal His42 residue in the catalytic mechanism of pea cytosolic ascorbate peroxidase, two site-directed variants were prepared in which His42 was replaced with alanine (H42A) or glutamic acid (H42E). Electronic spectra of the ferric derivatives of H42A and H42E (pH 7.0, l ¼ 0.10 M, 25.0 °C) revealed wavelength maxima [kmax (nm): 397, 509, % 540sh, 644 (H42A); 404, 516, % 538sh, 639 (H42E)] consistent with a predominantly fiveco-ordinate high-spin iron. The specific activity of H42E for oxidation of L-ascorbate (8.2 ± 0.

11p system191 01-06-2013 39 4   Download

Conventional and saturation transfer electron paramagnetic resonance spectroscopy (EPR and ST EPR) was used to study the orientation of probe molecules in muscle fibers in different intermediate states of the ATP hydrolysis cycle. A separate procedure was used to obtain ST EPR spectra with precise phase settings even in the case of samples with low spectral intensity. Fibers prepared from rabbit psoas muscle were labeled with isothiocyanate spin labels at the reactive thiol sites of the catalytic domain of myosin....

10p research12 01-06-2013 39 6   Download

Cytochrome P450foxy (P450foxy, CYP505) is a fused protein of cytochrome P450 (P450) and its reductase isolated from the fungus Fusarium oxysporum, which catalyzes the subterminal (x-1x-3) hydroxylation of fatty acids. Here, we produced, purified and characterized a fused recombinant protein (rP450foxy) using the Escherichia coli expression system. Purified rP450foxy was catalytically and spectrally indistinguishable from the native protein, but most of the rP450foxy was recovered in the soluble fraction of E. coli cells unlike the membrane-bound native protein....

8p research12 01-06-2013 58 4   Download

Thioredoxin is a ubiquitous dithiol oxidoreductase found in many organisms and involved in numerous biochemical processes. Human thioredoxin-like protein (hTRXL) is differentially expressed at different development stages of human fetal cerebrum and belongs to an expanding family of thioredoxins. We have solved the crystal structure of the recombinant N-terminal catalytic domain (hTRXL-N) of ˚ hTRXL in its oxidized form at 2.2-A resolution.

9p research12 01-06-2013 41 4   Download

Eukaryotic ribonuclease (RNase) H2 consists of one catalytic and two accessory subunits. Several single mutations in any one of these subunits of human RNase H2 cause Aicardi–Goutie`res syndrome. To examine whether these mutations affect the complex stability and activity of RNase H2, three mutant proteins of His-tagged Saccharomyces cerevisiaeRNase H2 (Sc-RNase H2*) were constructed. Sc-G42S*, Sc-L52R*, and Sc-K46W* contain single mutations in Sc-Rnh2Ap*, Sc-Rnh2Bp*, and Sc-Rnh2Cp*, respectively....

14p research12 29-04-2013 40 1   Download

F1-ATPase is inactivated by entrapment of MgADP in catalytic sites and reactivatedbyMgATPorPi.Here, usinga mutant a3b3c complex of thermophilic F1-ATPase (aW463F/bY341W) and monitoring nucleotide binding by ¯uorescence quenching of an introduced tryptophan, we found that P i interfered with the binding of MgATP to F1-ATPase, but binding ofMgADPwas interferedwith to a lesser extent.

8p research12 29-04-2013 37 4   Download

Theb1,3-glycosyltransferase enzymes identi®ed to date share several conserved regions and conserved cysteine res-idues, all being located in the putative catalytic domain. To investigate the importance of these motifs and cysteines for the enzymatic activity, 14 mutants of the murine b1,3-galactosyltransferase-I gene were constructed and expressed in Sf9 insect cells. Seven mutations abolished the galacto-syltransferase activity.

7p research12 29-04-2013 38 3   Download

Achromobacterprotease I (API) has a unique region of aromatic ring stacking with Trp169–His210in close proxi-mity to the catalytic triad. This paper reveals the electrostatic role of aromatic stacking in the shift in optimum pH to the alkaline region, which is the highest pH range (8.5–10) among chymotrypsin-type serine proteases. The pH-activity profile of API showed a sigmoidal distribution that appears at pH 8–10, with a shoulder at pH 6–8.

7p research12 23-04-2013 42 2   Download

From the membrane fraction of the Gram-positive bacter-ium Carboxydothermus hydrogenoformans,anenzyme complex catalyzing the conversionofCOtoCO2andH2was purified. The enzyme complex showed maximal CO-oxidi-zing:H2 -evolving enzyme activity with 5% CO in the head-space (450 U per mg protein). Higher CO concentrations inhibited the hydrogenase present in the enzyme complex. For maximal activity, the enzyme complex had to be activated by either CO or strong reductants.

10p tumor12 22-04-2013 38 2   Download

Metabolite channelling, the process in which consecutive enzymes have confined substrate transfer in metabolic pathways, has been proposed as a biochemical mechanism that has evolved because it enhances catalytic rates and protects unstable intermediates. Results from experiments on the synthesis of radioactive urea [Cheung, C., Cohen, N.S. & Raijman, L (1989)J. Biol. Chem.264, 4038–4044] have been interpreted as implying channelling of arginine between argininosuccinate lyase and arginase in permeabi-lized hepatocytes. ...

9p tumor12 20-04-2013 35 1   Download

The sulfonephthalein indicator, phenol red, exhibits an unusually slow rate of oxidation by laccase fromPolipo-rus pinsitus, in spite of the fact that it is a phenol and therefore a natural substrate for this phenoloxidase enzyme. Nevertheless, after prolonged exposure to laccase (24 h) phenol red is oxidized by more than 90%.

7p tumor12 20-04-2013 40 2   Download

Heterologous expression of the putative open reading frame MJ0303 ofMethanococcus jannaschiiprovided a recombin-ant protein catalysing the formation of the riboflavin precursor, 6,7-dimethyl-8-ribityllumazine, by condensation of 5-amino-6-ribitylamino-2,4(1H,3H)-pyrimidinedione and 3,4-dihydroxy-2-butanone 4-phosphate. Steady state kinetic analysis at 37
C and pH 7.0 indicated a catalytic rate of 11 nmolÆmg )1 Æmin )1 ;Kmvalues for 5-amino-6-ribitylamino-2,4(1H,3H)-pyrimidinedione and 3,4-dihydroxybutanone 4-phosphate were 12.5 and 52lM, respectively....

8p tumor12 20-04-2013 37 3   Download

Protein phosphatase 2A is a phosphoserine/threonine phosphatase implicated inmany cellular processes. The core enzyme comprises a catalytic and a PR65/A-subunit. The substrate specificity and subcellular localization are deter-mined by a third regulatory B-subunit (PR55/B, PR61/B¢ and PR72/130/B¢¢). To identify the proteins of the B¢¢family inXenopus laevisoocytes, aprophaseXenopusoocyte cDNA librarywas screened using humanPR130 cDNAas a probe. Three different classes of cDNAs were isolated....

12p tumor12 20-04-2013 28 3   Download

We have isolated and characterized a second [Fe]-hydro-genasegene fromthegreenalga,Chlamydomonas reinhardtii. TheHydA2gene encodes a protein of 505 amino acids that is 74% similar and 68% identical to the known HydA1 hydrogenase fromC. reinhardtii.HydA2 contains all the conserved residues and motifs found in the catalytic core of the family of [Fe]-hydrogenases. We demonstrate that both theHydA1and theHydA2transcripts are expressed upon anaerobic induction, achieved either by neutral gas purging or by sulfur deprivation of the cultures. ...

9p fptmusic 16-04-2013 47 2   Download