High pressure unfolding of ovalbumin

The effects of high pressure processing of ovalbumin have been investigated . After treatment with pressures in excess of 400 MPa at pH 6.5, circular d ichroism (CD) and Fourier transform infra-red spectroscopy (FTIR) spectrosc opy showed limited irreversible changes in secondary structure. Fluorescenc e and derivative spectroscopy as well as fluorescence-quenching experiments indicated greater solvent exposure of aromatic residues in pressure-treate d protein. Pressure treatment also caused enhanced binding of anilino-1-nap hthalene-8-sulphonic acid (ANS). The pressure necessary to cause these chan ges was lower at low pH. These data indicate a pressure-induced molten-glob ule formation. The pressurized protein may be structurally similar to forms of the protein found at acid pH or as intermediates in protein folding.