Regulation of Ester Synthesis Activity of Rhizopus chinensis Lipase

The regaining of ester synthesis catalytic ability of extracted and expressed Rhizopus chinensis lipase was investigated in this work. After de novo folding in a mimicking membrane environment, the maximum ester synthesis specific activity of extracted lipase precipitated protein ( eRCL-P ) was re-obtained and even increased for over 5 times. The refolding treatment of r27RCL, a Pichia pastoris expressed lipase with a high hydrolysis activity but low ester synthesis activity , with different membrane mimicking factors also increased the organic catalysis ability of the protein. The best enhancement of ester synthesis activity was shown when r27RCL was directly mixed with detergent, which indicated the interaction between lipase and regulation factor was established during mixing stage in water solution. Moreover, seven different detergents of three diversity types were introduced to confirm the result, and the zwitterionic detergent LPC14 increased the ester synthesis activity of r27RCL for the best effect as 5. 75 times. Although the circular dichroism spectrum showed that the secondary structure of r27RCL had no obviously changes, the molecular dynamics simulation demonstrated that, in organic reaction, the hydrogen bonds between the catalytic triad of r27RCL have been enhanced after mixing with detergent, which may therefore stimulate the ester synthesis activity of lipase. In addition, these results confirmed the regulation of lipase ester synthesis activity, which will surely establish the basics for further research and production.