High hydrostatic pressure induced cold inactivation of carboxypeptidase Y. Carboxypeptidase Y was fully active when exposed to subzero temperature at MPa; however, the enzyme became inactive when high hydrostatic pressure and subzero temperature were both applied. When the enzyme was treated at pressures higher than 300 MPa and temperatures lower than)5 C, it underwent an irreversible inactivation in which nearly 50% of the a-helical structure was lost as judged by circular dichroism spectral analysis
