The structural stability of cardosin A, a plant aspartic proteinase (AP) from Cynara cardunculus L., has been investigated by high-sensitivity differential scanning calorimetry, intrinsic fluorescence and circular dichroism spectroscopy, and enzymatic activity assays. Even though the thermal denaturation of cardosin A is partially irreversible, valid thermodynamic data can be obtained within a ...

Fourier transform infrared spectroscopy has been used to study the solution structure and thermal stability of the extracellular fragment of human transferrin receptor (tfRt) at extracellular and endosomal pH. At extracellular pH tfRt is composed of 56% alpha-helix, 19% beta-sheet and 14% turns. Upon acidification to endosomal pH the alpha-helical content of the protein is reduced and the beta-...

Trypsin (E.C.3.4.21.4) is a serine protease commonly used in proteomics for digestion of proteins. In the present study, the effect of nano-TiO2 on the conformation and catalytic activity of trypsin were studied. The thermal denaturation of trypsin has been investigated in the presence and absence of nano-TiO2 over the temperature range (293-373 K) at pH 3.0 and 7.25, using temperature scanning...

The effects of high temperatures on catalytic activity and binding abilities of crude Trichoderma reesei cellulases in solution and adsorbed to a cotton fabric were studied. Above optimum temperature of 508C, catalytic activities were severely diminished but the binding behaviour was not found to be adversely affected. In order to verify possible applications of cellulases adsorbed to cotton fa...

The amino acid composition and the physicochemical and functional properties of quinoa protein isolates were evaluated. Protein isolates were prepared from quinoa seed by alkaline solubilization (at pH 9, called Q9, and at pH 11, called Q11) followed by isoelectric precipitation and spray drying. Q9 and Q11 had high levels of essential amino acids, with high levels of lysine. Both isolates show...

Fluorescence spectroscopy was used to study some aspects of thermal denaturation of lactate dehydrogenase (LDH) from rabbit muscle, in the absence and presence of urea and NaCl. Thermal denaturation of LDH seems to be one step and a slightly reversible process. The solution pH has an important influence on the LDH thermal denaturation. The interaction of LDH enzyme with NADH ligand was also inv...

Lactoferrin (LF) is a multifunctional protein in the transferrin family that has been widely used food and pharmaceutical products. However, it susceptible to denaturation during thermal processing, which can diminish functionality bioavailability of LF final product. Coacervation with biopolymers demonstrated as promising approach protect from denaturation. This work aims study formation condi...

Tetratricopeptide repeat (TPR) is a structural motif mediating variety of protein-protein interactions. It has a high potential to serve as a small, stable and robust, non-immunoglobulin ligand binding scaffold. In this study, we showed the consensus approach to design the novel protein called designed tetratricopeptide repeat (dTPR), composed of three repeated 34 amino-acid tetratricopeptide m...

Phaseolus vulgaris phytohemagglutinin L is a homotetrameric-leucoagglutinating seed lectin. Its three-dimensional structure shows similarity with other members of the legume lectin family. The tetrameric form of this lectin is pH dependent. Gel filtration results showed that the protein exists in its dimeric state at pH 2.5 and as a tetramer at pH 7.2. Contrary to earlier reports on legume lect...

Thermal denaturation of a-Lactalbumin in the absence and presence of various concentrations of sucrose,sorbitol, glucose and galactose as sugar osmolytes were measured by monitoring changes in the absorptions thatcarried out in a Lambd 35 UV-Vis double beam spectrophotometer at pH 6.0. These measurements gave valuesof T., (midpoint of denaturation), AH., (enthalpy change at T.), and ACp (consta...