A stable partly denatured state of trypsin induced by high hydrostatic pressure

The effect of hydrostatic pressure on the unfolding of trypsin was studied by fluorescence spectroscopy under pressure from 1 to 7000 bar. It was found that, at pH 3.0 or pH 7.3, a stable partly denatured state of trypsin was obtained when the applied pressure was about 6.5 kbar. This transient denatured state did not show any enzymatic activity and was different from that denatured by 8 M urea or high temperature in both intrinsic fluorescence spectrum and 8-anilino-1-naphtalene sulfonate (ANS) binding, having some obvious characteristics of 2 molten globule state of protein. It was also found that the formation of this partly denatured state of trypsin was temperature dependent. Energenic values of the process were also given.