Date of Award

5-2016

Degree Type

Honors College Thesis

Department

Chemistry and Biochemistry

First Advisor

Douglas Masterson, Ph.D.

Advisor Department

Chemistry and Biochemistry

Abstract

Pig Liver Esterase is a cost effective enzyme for ester hydrolysis. In our group, it is vital for creating chiral molecules for the synthesis of unnatural amino acids of potential biological importance. It has been previously found that the enantiomeric excess (%ee) of the PLE hydrolysis reaction increases drastically with the addition of co-solvents that are able to both accept and donate hydrogen bonds. This research endeavors to see if substrates of enhanced hydrogen bonding ability also increase the stereoselectivity of PLE hydrolyses. Diester malonate was covalently linked with a furan ring in both the third and second position from the oxygen atom to test this. These two substrates are unable to donate hydrogen bonds, but they are able to accept them. It was found that the substrate with the furan in the second position gave an %ee of 70% with no added co-solvent while the substrate in the third position gave a racemic mixture with no added co-solvent. This hints that there may be an amino acid anchoring the substrate in the active site of PLE, which will favor the creation of one enantiomer over the other. When 2.0% ethanol co-solvent was used in the PLE hydrolysis reaction the %ee rose to around 35%. To complete the series, diester malonate will be combined with a pyrrole ring in the second position from the nitrogen atom, which can only donate hydrogen bonds. This substrate will then undergo PLE hydrolysis with and without co-solvent to see the reactions’ respective enantiomeric excesses.

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