Preparation and properties of glucose isomerase immobilized on Indion 48-R

Partially purified glucose isomerase from Streptomyces thermonitrificans when coupled to glutaraldehyde-activated Indion 48-R, retained 30-40% activity of the soluble enzyme. However, an approximately twofold increase in the activity could be achieved by binding the enzyme in the presence of glucose...

Full description

Saved in:
Bibliographic Details
Published in:Applied biochemistry and biotechnology 1993-01, Vol.42 (2-3), p.92-104
Main Authors: Deshmukh, S S, Dutta Choudhury, M, Shankar, V
Format: Article
Language:English
Subjects:
Streptomyces thermonitrificans
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Partially purified glucose isomerase from Streptomyces thermonitrificans when coupled to glutaraldehyde-activated Indion 48-R, retained 30-40% activity of the soluble enzyme. However, an approximately twofold increase in the activity could be achieved by binding the enzyme in the presence of glucose. Binding the enzyme to matrices presaturated with either glucose or fructose and influence of lysine modification on the activity of the soluble enzyme revealed that the comparatively low activity observed in case of the enzyme bound in the absence of substrate is the result of the nonspecific binding of either substrate or product to the matrix. Immobilization did not affect the pH and temperature optima of the enzyme, but it lowered the temperature stability. Immobilization resulted in a marginal increase in the K sub(m) and a threefold decrease in the V sub(max). Substrate concentrations as high as 36% glucose could be converted to 18.5% fructose in 5 h, at pH 7.0 and 70 degree C. The bound enzyme, however, showed inferior stability to repeated use and lost approx 40% of its initial activity after five cycles of use. Indion 48-R bound glucose isomerase could be stored, in wet state, for 30 d without any apparent loss in its initial activity. (DBO)
ISSN:0273-2289