Pineapple (Ananas comosus), Bromeliaceae family, is a fruit grows in tropical countries including Malaysia. This fruit has several pharmacological benefits due to the presence of high concentration of bromelain (cysteine proteases). Condition of elevated temperature will induce deformation of enzyme and result in loss of activity. Sulfhydryl groups in cysteine proteases are readily to be oxidiz...

The structural stability of a peroxidase, a dimeric protein from palm tree Chamaerops excelsa leaves (CEP), has been characterized by high-sensitivity differential scanning calorimetry, circular dichroism and steady-state tryptophan fluorescence at pH 3. The thermally induced denaturation of CEP at this pH value is irreversible and strongly dependent upon the scan rate, suggesting that this pro...

The thermally induced denaturation of DNA in the presence of an attractive solid surface is studied. The two strands of DNA are modeled via two coupled flexible chains without volume interactions. If the two strands are adsorbed on the surface, the denaturation phase transition disappears. Instead, there is a smooth crossover to a weakly naturated state. Our second conclusion is that even when ...

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-...

The thermal denaturation of ribonuclease A has been studied by use of Fourier transform nuclear magnetic resonance by monitoring the imidazole C-2 proton resonances of the histidine residues as a function of temperature at pH 1.3. As the temperature is raised, a slow chemical exchange process results in the disappearance of the peaks corresponding to the native conformation and the appearance o...

Release 4.0 of ProTherm, thermodynamic database for proteins and mutants, contains approximately 14,500 numerical data (approximately 450% of the first version) of several thermodynamic parameters along with experimental methods and conditions, and structural, functional and literature information. The sequence and structural information of proteins is connected with thermodynamic data through ...

Thermal stability of proteins During various industrial processes it is necessary for proteins to be temporarily placed under elevated temperatures. It is crucial to understand whether the protein of importance is stable at increased temperatures and whether the effects of increasing the temperature are reversible. The resistance of a protein to denaturation and its ability to refold are also m...

A statistical model of homopolymer DNA, coupling internal base-pair states (unbroken or broken) and external thermal chain fluctuations, is exactly solved using transfer kernel techniques. The dependence on temperature and DNA length of the fraction of denaturation bubbles and their correlation length is deduced. The thermal denaturation transition emerges naturally when the chain fluctuations ...

Differential scanning microcalorimetry was used to assess the conformational stability of muscle lactate dehydrogenase (M4-LDH) from skeletal muscle of Misgurnus fossilis (loach) fishes adapted to low (the “cold” enzyme) and high (the “warm” enzyme) environmental temperatures. It was found that the denaturation temperature Td was the same for both forms of lactate dehydrogenase, whereas the den...

Morita, Richard Y. (University of Nebraska, Lincoln) and Roger D. Haight. Malic dehydrogenase activity at 101 C under hydrostatic pressure. J. Bacteriol. 83:1341-1346. 1962.-No malic dehydrogenase activity was found to occur at 101 C at various hydrostatic pressures from 1 to 700 atm. However, activity was demonstrated with hydrostatic pressures above 700 atm, with optimal activity at 1,300 atm...