Pig Liver Esterase (PLE) is widely used in synthesis due to its low cost, stability, and ability to accept various substrates. PLE is composed of at least 6 isoenzymes; however, the role of each in crude PLE is not yet well understood. It has been demonstrated that the addition of co-solvents to the buffer can dramatically alter the enantiomeric excess (ee) of the reaction. Addition of just 2% EtOH into hydrolysis of (1)  increased the enantiomeric excess from 23 %ee to 85 %ee. This increase in enantioselectivity is substrate specific. Addition of co-solvent to the reaction with (2)   showed moderate increases in enantioselectivity, while addition of co-solvent to the reaction with (3)  did not show any effect. We propose that as hydrogen bonding ability of the substrate decreases, the ability of EtOH to influence the enantioselective outcome of the reaction is decreased. NMR titrations have been conducted to measure the extent of hydrogen bonding between substrate and co-solvent. ?

Investigation of co-solvent effects on the selectivities of PLE isoenzymes with various substrates

245th National Meeting (2013)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.