Extracellular invertase (EC 3.2.1.26) of Saccharomyces cerevisiae was stabilized against thermal denaturation by intermolecular and intramolecular crosslinking of the surface nucleophilic functional groups with diisocyanate homobifunctional reagents (O==C==N(CH(2))(n)N==C==O) of various lengths (n = 4, 6, 8). Crosslinking with 1,4-diisocyanatobutane (n = 4) proved most effective in enhancing th...

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...

Rhodopsin, the red photosensitive pigment of rod vision, is composed of a specific cis isomer of retinene, neo-b (ll-c~s), joined as chromophore to a colorless protein, opsin. We have investigated the thermal denaturation of cattle rhodopsin and opsin in aqueous digitonin solution, and in isolated rod outer limbs. Both rhodopsin and opsin are more stable in rods than in solution. In solution as...

The thermal denaturation of laccase from the Japanese lacquer tree (Rhus vernicifera) was studied by differential scanning calorimetry. The endotherms of holo-laccase, type 2-Cu-depleted laccase and apo-laccase were deconvoluted into two independent two-state transitions, providing evidence for a domain structure of the protein. The correlation of the two transitions with the bleaching of coppe...

Rhodopsin, the red photosensitive pigment of rod vision, is composed of a specific cis isomer of retinene, neo-b (11-cis), joined as chromophore to a colorless protein, opsin. We have investigated the thermal denaturation of cattle rhodopsin and opsin in aqueous digitonin solution, and in isolated rod outer limbs. Both rhodopsin and opsin are more stable in rods than in solution. In solution as...

Recently, thermal treatment has been used for collagen tightening and tissue contour enhancement. It is important to monitor the condition of collagenous tissue during and immediately after thermal treatment. When collagen is denatured, birefringence is reduced and a change in polarization state occurs. In this study, Monte Carlo simulation for polarized light was used to calculate the degree o...

The thermal denaturation of lysozyme in aqueous alcohol solutions has been investigated through ultraviolet difference spectrophotometry and optical rotation measurements. Alcohols used were CH30H, C2H50H, and C3H70H; concentrations up to 50% (v/v) of alcohol in water were employed. It was found that upon increasing the size or the concentration of the aliphatic alcohol, the denaturation temper...

Human acidic fibroblast growth factor (FGF-1) is a powerful mitogen and angiogenic factor with an apparent melting temperature (Tm) in the physiological range. FGF-1 is an example of a protein that is regulated, in part, by stability-based mechanisms. For example, the low Tm of FGF-1 has been postulated to play an important role in the unusual endoplasmic reticulum-independent secretion of this...

Recent studies have shown that shockwave heating and millisecond boiling in high-intensity focused ultrasound fields can result in mechanical fractionation or emulsification of tissue, termed boiling histotripsy. Visual observations of the change in color and contents indicated that the degree of thermal damage in the emulsified lesions can be controlled by varying the parameters of the exposur...

The interaction between nano-SiO2 and lysozyme was investigated by the method of UV-Visible  detection and fluorescence spectroscopic techniques. The thermal denaturation of lysozyme has been investigated in the presence and absence of nano-SiO2 over the temperature range (293-373) K in different buffers and pH values, using temperature scanning spectroscopy. The presence of nano-SiO2 caused th...