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The mechanism of inactivation of glucose oxidase from Penicillium amagasakiense under ambient storage conditions

Paper ID Volume ID Publish Year Pages File Format Full-Text
17560 42677 2011 9 PDF Available
Title
The mechanism of inactivation of glucose oxidase from Penicillium amagasakiense under ambient storage conditions
Abstract

Glucose oxidase (GOx) from Penicillium amagasakiense has a higher specific activity than the more commonly studied Aspergillus niger enzyme, and may therefore be preferred in many medical and industrial applications. The enzyme rapidly inactivates on storage at pH 7.0–7.6 at temperatures between 30 and 40 °C. Results of fluorimetry and circular dichroism spectroscopy indicate that GOx inactivation under these conditions is associated with release of the cofactor FAD and molten globule formation, indicated by major loss of tertiary structure but almost complete retention of secondary structure. Inactivation of GOx at pH < 7 leads to precipitation, but at pH ≥ 7 it leads to non-specific formation of small soluble aggregates detectable by PAGE and size-exclusion chromatography (SEC). Inactivation of P. amagasakiense GOx differs from that of A. niger GOx in displaying complete rather than partial retention of secondary structure and in being promoted rather than prevented by NaCl. The contrasting salt effects may reflect differences in the nature of the interface between subunits in the native dimers and/or the quantity of secondary structure loss upon inactivation.

Keywords
ANS, 1-anilino-8-naphthalene sulphonate; GOx, glucose oxidase; kDa, kilodaltons; MRE, mean residue ellipticity; RFI, relative fluorescence intensity; SEC, size exclusion chromatography; Trp, tryptophanAggregation; Glucose oxidase (GOx); Inactivation; Dena
First Page Preview
The mechanism of inactivation of glucose oxidase from Penicillium amagasakiense under ambient storage conditions
Publisher
Database: Elsevier - ScienceDirect
Journal: Enzyme and Microbial Technology - Volume 49, Issue 1, 10 June 2011, Pages 79–87
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Bioengineering