Circular dichroism studies of Escherichia coli pyruvate oxidase and secondary structure and lipid binding properties of the alpha peptide from pyruvate oxidase

Pyruvate oxidase, a tetrameric enzyme consisting of four identicle subunits, undergoes a change in conformation with the binding of TPP and pyruvate. Circular dichroism measurements show the change in secondary structure with this ligand induced conformational change. Circular dichroism spectra also change with the addition of phospholipid vesicles which bring about an increase in catalytic activity. The circular dichroism spectra for detergent activated and proteolytically activated pyruvate oxidase are virtually identicle indicating there is a further change to the maximally activated conformation of the enzyme. Circular dichroism spectra obtained with varying levels of phospholipid vesicles which activate the enzyme to varying levels give patterns which vary between the minimally and maximally activated spectra. These spectra positively correlate with the level of enzyme activity. Activation of pyruvate oxidase with HFP, a hydrophobic region disruptor, also alters the circular dichroism spectra to a degree consistent with that of lipid activation at similar activity levels. This indicates that the removal of the alpha-peptide region of pyruvate oxidase from the catalytic site brings about a change in conformation which maximally activates the enzyme. Lower activity levels is seen with smaller changes in conformation.

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2011

Author dc:creator

• Schuh, William Kenneth

Contributors dc:contributor

• Hager, Lowell P.

• Chemistry, Biochemistry

Statement dc:rights

• Copyright 1992 Schuh, William Kenneth

Language dc:language

eng

Identifier

AAI9305685
(UMI)AAI9305685

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/22029