The effects of high hydrostatic pressure (HHP) and urea on conformational transitions of humana-thrombin structure were studiedbyfluorescence spectroscopy andbymeasuring the catalytic activity of the enzyme. Treatment of thrombin with urea produced a progressive red shift in the center of mass of the intrinsic fluorescence emission spectrum, with a maximum displacement of 650 cm )1 . HHP (270 MPa) shifted the centre ofmass by only 370 cm )1 .HHP combined with a subdenaturing urea concentration () displaced the centre of mass by 750 cm )1
