Elucidation of pressure-induced lid movement and catalysis behavior of Rhizopus chinensis lipase

- Computational and experimental methods were used to study the pressure effect on the movement of Rhizopus chinensis lipase lid and the interfacial behaviour.
- The displayed pressure effect on interfacial activation was studied and confirmed for the first time.
- It is tempted to study the hydrolytic kinetics of the lipase after HHP treatment in addition to the activity change.

The changes of lid movement and catalysis behavior of Rhizopus chinensis lipase under high hydrostatic pressure treatment was studied. Molecular dynamics simulation showed that the lipase lid under pressure was partially opened at below 200 MPa but got more closed at over 400 MPa. The interfacial activation changed little at pressure below 400 MPa but became marginal with the pressure increased to 500 MPa. The lipase hydrolysis ability by high pressure treatment underwent a course of initial increasing then reducing with maximum activity obtained at 200 MPa and 40 °C. At moderate given pressure, the pressure treatment lowered the volume between the reactants and the transition state. Km decreased from 0.592 to 0.441 mmol/L with pressure increasing from 0.1 to 200 MPa. Meanwhile, vmax and Kcat increased 24.2% and 20% respectively. The change trend of reaction kinetic parameters under 400-500 MPa was contrary to that under 0.1-200 MPa.