The partial-denaturation map of T4 DNA is obtained by using benzyldodecyldimethyl ammonium chloride in the presence of a high concentration of formamide. In this way suitable conditions for preparation of electron microscope specimens and partial denaturation within a temperature range low enough to minimize the endonucleolytic cleavage, are realized. It is found that, under our experimental co...

Protein stabilizing potential of honey was studied on a model protein, bovine serum albumin (BSA), using extrinsic fluorescence of fluorescein isothiocyanate (FITC) as the probe. BSA was labelled with FITC using chemical coupling, and urea and thermal denaturation studies were performed on FITC-labelled BSA (FITC-BSA) both in the absence and presence of 10% and 20% (w/v) honey using FITC fluore...

The kinetics of thermal denaturation of a biliprotein, C-phycocyanin (C-PC) isolated from Spirulina platensis were studied at different pH values, ranging from 4.0 to 8.0. The denaturation of C-PC follows the first order kinetics and rate constant at pH 5.0 and temperature 55 degrees C is found to be 4.37 x 10(-5) s(-1), which increases to 5.46 x 10(-1) s(-1) at pH 7.0. The denaturation rate is...

Macromolecular crowding ought to stabilize folded forms of proteins, through an excluded volume effect. This explanation has been questioned and observed effects attributed to weak interactions with other cell components. Here we show conclusively that protein stability is affected by volume exclusion and that the effect is more pronounced when the crowder's size is closer to that of the protei...

Experimental data show that the effect of temperature on enzymes cannot be adequately explained in terms of a two-state model based on increases in activity and denaturation. The Equilibrium Model provides a quantitative explanation of enzyme thermal behaviour under reaction conditions by introducing an inactive (but not denatured) intermediate in rapid equilibrium with the active form. The tem...

Whey, a byproduct of the cheesemaking process, is concentrated by processors to make whey protein concentrates (WPC) and isolates (WPI). Only 50% of whey proteins are used in foods. In order to increase their usage, texturizing WPC, WPI, and whey albumin is proposed to create ingredients with new functionality. Extrusion processing texturizes globular proteins by shearing and stretching them in...

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...

embedding a fast-response microthermocouple inside a PCR reaction tube, we were able to study the thermodynamic process from the block via the tube to the PCR sample in more detail. This physical evaluation allowed us to distinguish accurate performers (category 1 and 2 cyclers) from less accurate performers (category 3 cyclers). At the denaturation step, during the first 15 s the thermal inhom...

The change produced in native proteins by various agents which results in loss of their characteristic properties and changes in solubility is called denaturation. The term, however, may be applied to structural and physical changes in the protein molecule which differ widely with the particular agent used. Urea denaturation differs in many respects from both heat and radiation denaturation. Ur...

Rates of formation of RNA:DNA hybrids have been measured as a function of temperature and compared to DNA:RNA duplex denaturation temperatures in 4 M sodium perchlorate, 4 M NaClO4-6 M urea, and 3 M rubidium trichloracetate solvents. The usual bell shaped curves of reaction rate versus temperature were observed. The optimal temperatures for the RNA:DNA association reaction are 5 degrees to 12 d...