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Document Type

Research

Keywords

fusion proteins, purification fusions, protein purification, ion exchange membrane

Abstract

Our research examined whether enhanced separation and purification of mutant enzymes could be obtained on ion-exchange membranes. Solutions of three mutants of Aspergillus awamori glucoamylase were passed through an anionic exchange membrane, as well as one mutant of T4 lysozyme through a cationic exchange membrane. The mutant enzymes were modified by adding "charged fusions'', polypeptides of either aspartic acid residues to increase the overall negative charge of the enzyme or arginine residues to increase the overall positive charge. The effect of the mutations on the purification of glucoamylase from a "modified" fermentation broth were examined at two different elution pHs, 4.5 and 6.0.

The use of the charged fusions provided significantly improved purification capabilities over control versions. Both the small scale glucoamylase runs and the scaled up experiments had overall purification factors of around two, with a peak purification factor of near 7 for GA'CDlO. Elution of glucoamylase at pH 4.5 did not lead to an increase in separability as compared to that obtained at pH 6.0.

Initial trials using a purified lysozyme mutant showed significant binding capabilities. Further experiments with this protein need to be done to determine scale up potential.

Publication Date

June 1994

Journal Title

Journal of the Iowa Academy of Science

Volume

101

Issue

2

First Page

61

Last Page

65

Copyright

© Copyright 1994 by the Iowa Academy of Science, Inc.

Language

EN

File Format

application/pdf