Oxidative stability

This study examined the effectiveness of different antioxidative compounds, namely 0.2% BHA (Butylated hydroxyanisole) + BHT (butylated hydroxytoluene), 0.03% α – tocopherol, and 3% and 6% tea seed oil (TSO) on the oxidative stability of vegetable oils. Four commonly used oils, viz. rapeseed oil (RSO), peanut oil (PNO), sunflower oil (SFO), and soybean oil (SBO), were assessed by the Schall Oven test method and monitored during the 12-day preservation period under 60°C.

10p chauchaungayxua12 09-07-2021 14 2   Download

The purpose of the thesis: Understanding and building manufacturing technology for positive material, which has the ability to exchange and storage of Li+ , Na+ on manganese oxide substrate. Investigating the variation of electrical and electrochemical properties of material systems dependent on technological factors. Therefore, determining the suitable technology for making conductor material and charge/discharge Li+ , Na+ ion with high capacity, energy density, and structural stability.

27p xacxuoc4321 09-07-2019 45 4   Download

Heterologous expression of the extracellular domains (ECDs) of the nicotinic acetylcholine receptor (AChR) subunits may give large amounts of proteins for studying the functional and spatial characteristics of their ligand-binding sites. The ECD of the a7 subunit of the homo-oligomeric a7 neuronal AChR appears to be a more suitable object than the ECDs of other heteromeric neuronal or muscle-type AChRs. The rat a7 ECDs (amino-acid residues  1–210) were recently expressed in Escherichia coli as fusion proteins with maltose-binding protein...

9p system191 01-06-2013 39 3   Download

To establish an infection, Yersinia pseudotuberculosis utilizes a plasmid-encoded type III secretion machine that permits the translocation of several anti-host factors into the cytosol of target eukaryotic cells. Secreted YopD is essential for this process. Pre-secretory stabilization of YopD is mediated by an interaction with its cognate chaperone, LcrH. YopD possesses LcrH binding domains located in the N-terminus and in a predicted amphipathic domain located near the C-terminus. This latter domain is also critical for Yersinia virulence. ...

10p research12 01-06-2013 51 3   Download

Fibritin is a segmented coiled-coil homotrimer of the 486-residue product of phage T4 gene wac. This protein attaches to a phage particle by the N-terminal region and ˚ forms fibrous whiskers of 530 A, which perform a chaperone function during virus assembly. The short C-terminal region has a b-annulus-like structure. We engineered a set of fibritin deletion mutants sequentially truncated from the N-termini, and the mutants were studied by differential scanning calorimetry (DSC) and CD measurements....

9p research12 01-06-2013 44 3   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

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 49 3   Download

When theaand bchains were separated from human oxyhemoglobin (HbO2), each individual chain was oxidized easily to the ferric form, their rates being almost the same with a very strong acid-catalysis. In the HbO2tetramer, on theother hand, bothchains become considerably resistant to autoxidation over a wide range of pH values (pH 5±11).

10p research12 29-04-2013 43 4   Download

It is scientifically and industrially important 1 to clarify the stabilizing mechanism of proteases in extraordinary envi-ronments. We used subtilisins ALPI and Sendai as models to study the mechanism. Subtilisin ALPI is extremely sensitive to highly alkaline conditions, even though the enzyme is produced by alkalophilicBacillus, whereas sub-tilisin Sendai from alkalophilic Bacillusis stable under conditions of high alkalinity.

9p research12 23-04-2013 49 2   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

Mammalian tubulins and actins attain their native con-formation following interactions with CCT (the cytosolic chaperonin containing t-complex polypeptide 1). To study the b-tubulin folding in lower eukaryotes, an isotype of b-tubulin (b-T1) from the Antarctic ciliate Euplotes focardii, was expressed in Escherichia coli. Folding analysis was performed by incubation of the 35 S-labeled, denatured b-T1 in the presence, or absence, of purified rabbit CCT and cofactor A, a polypeptide that stabilizes folded monomericb-tubulin. ...

7p tumor12 22-04-2013 52 3   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

One of the most drastic post-translational modification of proteins in eu-karyotic cells is poly(ADP-ribosyl)ation, catalysed by a family enzymes termed poly(ADP-ribose) polymerases (PARPs). In the human genome, 18 different genes have been identified that all encode PARP family members.

14p fptmusic 11-04-2013 53 2   Download

We investigated the role of electrostatic charges at positions D72 and K8 in the function and structural stability of cytochrome c6 from Nostocsp. PCC 7119 (cytc6). A series of mutant forms was generated to span the possible combinations of charge neutralization (by mutation to alanine) and charge inversion (by mutation to lysine and aspartate, respectively) in these positions.

11p fptmusic 11-04-2013 51 5   Download

A structural motif called the small exterior hydrophobic cluster (SEHC) has been proposed to explain the stabilizing effect mediated by solvent-exposed hydrophobic residues; however, little is known about its biological roles. Unusually, in D 5 -3-ketosteroid isomerase from Pseudomonas putida biotype B (KSI-PI) Trp92 is exposed to solvent on the protein surface, forming a SEHC with the side-chains of Leu125 and Val127.

13p awards 06-04-2013 36 3   Download

3-Phosphoglycerate kinase (PGK) is a typical two-domain hinge-bending enzyme with a well-structured interdomain region. The mechanism of domain–domain interaction and its regulation by substrate binding is not yet fully understood. Here the existence of strong cooperativity between the two domains was demonstrated by following heat transitions of pig muscle and yeast PGKs using differential scanning microcalorimetry and fluorimetry.

19p awards 06-04-2013 55 4   Download

Neurotransmitter transporters play a major role in achieving low concen-trations of their respective transmitter in the synaptic cleft. The GABA transporter GAT1 belongs to the family of Na + - and Cl – -coupled trans-port proteins which possess 12 putative transmembrane domains and three N-glycosylation sites in the extracellular loop between transmembrane domain 3 and 4.

0p awards 06-04-2013 38 3   Download

Why are there so many dimeric proteins and enzymes? While for hetero-dimers a functional explanation seems quite reasonable, the case of homo-dimers is more puzzling. The number of homodimers found in all living organisms is rapidly increasing. A thorough inspection of the structural data from the available literature and stability (measured from denatura-tion–renaturation experiments)

0p awards 05-04-2013 44 2   Download

Substitution oftrans-proline at three positions in ubiquitin (residues 19, 37 and 38) produces significant context-dependent effects on protein stability (both stabilizing and destabilizing) that reflect changes to a combination of parameters including backbone flexibility, hydrophobic interactions, solvent accessibility to polar groups and intrinsic backbone conformational preferences. Kinetic analysis of thewild-type yeast protein reveals a predominant fast-folding phase which conforms to an apparent two-state folding model. ...

11p awards 05-04-2013 49 4   Download

The structural stability of the large cytoplasmic domain (H4 -H5loop) of mouse a1subunit of Na + /K + ATPase (L354– I777), the number and the location of its binding sites for 2¢-3¢-O-(trinitrophenyl) adenosine 5¢-triphosphate (TNP-ATP) andp-nitrophenylphosphate (pNPP) were investi-gated. C- and N-terminal shortening revealed that neither part of the phosphorylation (P)-domain are necessary for TNP-ATP binding.

14p awards 05-04-2013 46 5   Download