The protein denaturation under high pressure : effects of ph and some substances on the pressure denaturation of ovalbumin solution

The effects of the pH and of the various added substances on the pressure denaturation of ovalbumin solution were examined by measuring the solubility as an index. The results are as follows: Ovalbumin has the maximum stability near pH 9 toward pressure-denaturation, the rate of pressure denaturation reaction of ovalbumin is proportional to the square root of hydrogen-ion concentration independently of the treated pressure and temperature, and the activation volumes are negative and the values depend on temperature but not on pH. Sulfate and glucose are inhibitors, and urea and ethyl alcohol are accelerators for pressure denaturation. And a little amount of calcium chloride and sodium chloride accelerates the pressure denaturation, but a large amount of them tend to inhibit it

Optical studies of pressure effects I : the measurement of the O-H stretching vibration band of ethanol

The infrared spectra near 3 micron of ethanol in solution were measured up to 8000kg/cm^2. The main pressure effects observed were the shifts of the absorption maxima and the increase of intensities. The effect of pressure on the mean potential energy of the hydroxyl group due to environments is discussed from the shifts. The effect of pressure on the equilibrium between monomeric and associated alcohol is estimated from the intensity changes

Optical studies of pressure effects : III. Pressure effect on the aqueous solution of amylose-iodine complex

The absorption spectrum of an aqueous solution of amylose-iodine complex was measured under high pressure up to 4000kg/cm^2. The absorption intensity at 620mμ decreases with increase of pressure and the intensity does not return to its initial value at normal pressure. It is not reasonable to regard this change as induced by the transition from helix to random-coil configuration of amylose molecules, judging from the result concerning the viscosity change and the pressure effect on the solution containing only amylose. It may be considered qualitatively that this change is due to the shift of the equilibrium between free I_2 and I_3 in the complex solution under high pressure