Abstract:
Carica papaya lipase (CPL) was explored as an effective enantioselective biocatalyst for the hydrolytic resolution of (R,S)profen esters in watersaturated organic solvents. Firstly, HPLC method was developed for determining the precise conversion and enantiomeric excess of profens and its esters. Kinetic analysis revealed the molecular basis of CPL catalyzed resolution of profen esters. Kinetic analysis of the CPL catalyzed resolution indicated that the enantioselectivity was due to the different reaction rates of the two isomers, not the different Km of the the two isomers. For naprofen the quotient of k2R/k2S was 195 which was approximately equal to the E value 173. Therefore, substrate structure had profound influences on enantioselectivity. Excellent enantioselectivity was found for substrates that contained a bulky substituent at the metaposition of 2phenyl moiety of the acyl part. For naproxen, the conversion reached up to 49% after 30 h reaction in nhexane with excellent enantioselectivity(E=173).