High thermal stability

The catalyst 7.5% NiO/TiO2 and seven samples of NiO/γ-Al2O3 with NiO content from 7.5% to 60% have been obtained and studied. Physico-chemical characteristics of the catalysts were determined by methods of Adsorption (BET), X-ray Diffraction (XRD), TemperatureProgrammed Reduction (TPR) and Hydrogen Pulse Titration. The catalytic properties of the obtained samples were investigated in the reaction of CO methanation at temperatures 180 – 220◦C and mole ratios hydrogen/carbon monoxide 25-100.

16p 12120609 01-06-2020 9 1   Download

The thermal stabilityofperoxidase fromleavesof theAfrican oil palm treeElaeis guineensis(AOPTP) at pH 3.0 was studied by differential scanning calorimetry (DSC), intrinsic fluorescence, CD and enzymatic assays.The spectral parameters asmonitoredby ellipticity changes in the far-UV CD spectrum of the enzyme as well as the increase in tryp-tophan intensity emission upon heating, together with changes in enzymatic activity with temperature were seen to be good complements to the highly sensitive but integral methodofDSC....

7p research12 29-04-2013 45 3   Download

The proposed biological function ofb-lactoglobulins as transporting proteins assumes a binding ability for ligands andhighstabilityunder theacidic conditionsof the stomach. This work shows that the conformational stability of non-ruminant porcine b-lactoglobulin (BLG) is not consistent with this hypothesis. Thermal denaturation of porcine BLG was studied by high-sensitivity differential scanning calori-metry within the pH range 2.0–10.0.

11p research12 23-04-2013 44 5   Download

The crystal structures of thermophilic xylanases from Chaetomium thermophilumandNonomuraea flexuosawere determined at 1.75 and 2.1 A˚ resolution, respectively. Both enzymes have the overall fold typical to family 11 xylanases with two highly twistedb-sheets forminga large cleft. The comparison of 12 crystal structures of family 11 xylanases from both mesophilic and thermophilic organisms showed that the structures of different xylanases arevery similar.

14p tumor12 20-04-2013 37 3   Download

To probe the stability of the seven-iron ferredoxin from Thermus thermophilus(FdTt), we investigated its chemical and thermal denaturationprocesses insolution.Aspredicted from the crystal structure, FdTt is extremely resistant to perturbation. The guanidine hydrochloride-induced unfolding transition shows a midpoint at 6.5M(pH 7, 20
C), andthe thermalmidpoint is aboveboiling, at 114
C. The stability of FdTt is much lower at acidic pH, suggesting that electrostatic interactions are important for the high stability at higher pH.

8p fptmusic 12-04-2013 59 5   Download

Neuroglobin (Ngb) and cytoglobin (Cygb), recent additions to the globin family, display a hexa-coordinated (bis-histidyl) heme in the absence of external ligands. Although these proteins have the classical globin fold they reveal a very high thermal stability with a melting temperature (Tm)of 100
C for Ngb and 95
C for Cygb. Moreover, flash photolysis experi-ments at high temperatures reveal that Ngb remains functional at 90
C

9p awards 06-04-2013 32 3   Download

We have studied the stability of the histone-like, DNA-binding protein HU from the hyperthermophilic eubacteriumThermotoga maritimaand its E34D mutant by differential scanningmicrocalorimetry and CDunder acidic conditions at various concentrations within the range of 2–225lMof monomer. The thermal unfolding of both proteins is highly reversible and clearly follows a two-state dissociation/unfolding model from the folded, dimeric state to the unfolded, monomericone.

11p dell39 03-04-2013 47 4   Download

Life grows almost everywhere on earth, including in extreme environments and under harsh conditions. Organisms adapted to high temperatures are called thermophiles (growth temperature 45–75C) and hyperthermophiles (growth temperature ‡80C). Proteins from such organisms usually show extreme thermal stability, despite having folded structures very similar to their mesostable counterparts.

11p media19 04-03-2013 52 3   Download

The hypothesis is tested that Jun–Fos activator protein-1 coiled coil inter-actions are dominated during late folding events by the formation of intri-cate intermolecular electrostatic contacts. A previously derived cJun–FosW was used as a template as it is a highly stable relative of the wild-type cJun–cFos coiled coil protein (thermal melting temperature = 63C versus 16C), allowing kinetic folding data to be readily extracted.

14p vinaphone15 27-02-2013 42 4   Download

Post-translational glycosylation is one of the most abundant forms of cova-lent protein modification in eukaryotic cells. It plays an important role in determining the properties of proteins, and stabilizes many proteins against thermal denaturation. Protein glycosylation may establish a surface micro-environment that resembles that of unglycosylated proteins in concentrated solutions of sugars and other polyols.

9p mobifone23 21-01-2013 45 4   Download