High pressure unfolding of ovalbumin

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Abstract
Summary 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 dichroism (CD) and Fourier transform infra‐red spectroscopy (FTIR) spectroscopy showed limited irreversible changes in secondary structure. Fluorescence and derivative spectroscopy as well as fluorescence‐quenching experiments indicated greater solvent exposure of aromatic residues in pressure‐treated protein. Pressure treatment also caused enhanced binding of anilino‐1‐naphthalene‐8‐sulphonic acid (ANS). The pressure necessary to cause these changes was lower at low pH. These data indicate a pressure‐induced molten‐globule formation. The pressurized protein may be structurally similar to forms of the protein found at acid pH or as intermediates in protein folding.