Partial purification of a lipase from Rhizopus arrhizus: a preliminary study on its enantioselectivity towards the hydrolysis of a methyl ester of a racemic arylpropionic acid

Date

3-1999

Degree

Bachelor of Science in Chemistry

College

College of Arts and Sciences (CAS)

Adviser/Committee Chair

Ma. Jamela R. Revilleza

Co-adviser

Milagros M. Peralta

Abstract

An extracellular lipase was partially purified from a strain of Rhizopus arrhizus and used as a catalyst in the hydrolysis of the methyl ester of a racemic arylpropionic acid. The crude enzyme was partially purified by Ammonium sulfate (AS) fractionation alone or in combination with DEAE-cellulose chromatography. High lipase activities were observed in the 100% AS supernatant fraction (100S, 1,226.8 U/mg) and the DEAE-cellulose chromatography bound fraction of the crude enzyme eluted with 1 0 M NaCI (CR 1.0M, 187. 8 U/mg). DEAE-cellulose chromatography of 100S resulted in the localization of activity in the fraction eluted by 0.8 M NaCI (100S 0.8 M, 512.1 U/mg). These observations indicated the inherent sensitivity of the enzyme to ion type and concentration, as well as the presence of other components in the buffer Crude enzyme and fractions with high lipase activities were used to catalyze the hydrolysis of a methyl ester of a racemic arylpropionic acid Analyses of the hydrolysis products revealed that there was no appreciable activity and selectivity. This enzyme may have different substrate specificities which need to be explored SDS-PAGE analysis revealed a partial purification of the enzyme after AS precipitation due to the decrease in the number of contaminating protein bands. Predominant bands have molecular weights of 21, 24 , 25 and 63 kD. However fractions from subsequent steps which had lipolytic activities needed a pre-concentration step prior to analysis to show a definite profile on the gel.

Language

Filipino

Location

UPLB Main Library Special Collections Section (USCS)

Call Number

Thesis

Document Type

Thesis

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