Function of a cloned polyphenolase in organic synthesis

Naidoo, Michael Joseph (1995) Function of a cloned polyphenolase in organic synthesis. Masters thesis, Rhodes University.

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Abstract

The enzyme polyphenolase, which catalyses the oxidation of phenols to catechols and subsequently dehydrogenates these to o-quinones, is widely distributed in nature. The multicopy plasmid vector pIJ702 contains a mel gene from Streptomyces antibioticus, that codes for the production of a polyphenol oxidase. The plasmid was isolated from Streptomyces lividans 66pIJ702 and subjected to a variety of mutagenic treatments in order to establish a structurefunction relationship for the polyphenolase enzymes. An attempt was made to engineer the polyphenolase enzyme by localized random mutagenesis in vitro of the mel gene on pIJ702, in order to alter properties like productivity, activity and substrate specificity. It was hoped to alter the amino acid sequence of the active site of the enzyme in order to facilitate catalysis in an organic environment. The plasmid was subsequently transformed into a plasmid-free Streptomyces strain, and enzyme production was carried out in batch culture systems, in order to determine the effect of the height treatment, and to isolate and propagate functional polyphenolase mutants for organic synthesis.

Item Type:Thesis (Masters)
Uncontrolled Keywords:Polyphenols, Catechol, Plasmids, Mutagenesis
Subjects:Q Science > QD Chemistry > QD241 Organic chemistry > QD415 Biochemistry
Divisions:Faculty > Faculty of Science > Biochemistry, Microbiology & Biotechnology
Supervisors:Kirby, Ralph
ID Code:3968
Deposited By: Mrs Carol Perold
Deposited On:06 Nov 2012 09:35
Last Modified:06 Nov 2012 09:35
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