Anders Hamberg

Rational engineering of Candida antarctica lipase B for selective monoacylation of diols

The enzyme Candida antarctica lipase B was subjected to site directed mutagenesis suggested by molecular modelling. The selectivity for the enzyme increased towards a range of diols over their corresponding monoesters as an effect of the mutations.

Selective Monoacylation of Diols by Substrate Assisted Catalysis in T40A Candida antarctica Lipase B

The selectivity towards diols over monoesters in the esterification of diols catalysed by lipase B from Candida antarctica (CALB) was improved by the single point mutation T40A in the enzyme’s oxyanion hole. Substrate‐assisted catalysis was suggested from molecular modelling of the tetrahedral intermediate in esterification of 1,2‐ethanediol catalysed by T40A CALB. The non‐reacting hydroxyl group of the diol forms a hydrogen bond to the oxyanion in the transition state, replacing that deleted in mutation. Monoester yields in transacylation reactions were monitored over time to compare the selectivities for wild‐type and T40A CALB. The results showed increased selectivities towards the diols tested over their corresponding monoesters as a result of the T40A mutation with substrate‐assisted catalysis as a plausible explanation.