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Purines oxidation by immobilized xanthine oxidase on magnetic polysiloxane–polyvinyl alcohol composite

Paper ID Volume ID Publish Year Pages File Format Full-Text
41581 45893 2011 5 PDF Available
Title
Purines oxidation by immobilized xanthine oxidase on magnetic polysiloxane–polyvinyl alcohol composite
Abstract

Bovine milk xanthine oxidase (XOD, E.C. 1.17.3.2) was covalently immobilized, via glutaraldehyde, on magnetic polysiloxane–polyvinyl alcohol (mPOS–PVA) particles yielding a preparation containing 9.5 ± 0.5 μg of protein per mg of support and specific activity of 36.3 ± 7.8 mU/mg of protein (55.0 ± 11.7% of the free enzyme). Optimal pH (8.8) and temperature (60 °C) were slightly higher than those established for the free enzyme (8.2 and 55 °C, respectively). No decrease of activity was observed after five reuses and only 17% was lost at the tenth reuse. The apparent Michaelis constant estimated for the mPOS–PVA–XOD (8.86 ± 0.88 μM) was not statistically different from the free enzyme (7.48 ± 1.01 μM). The 6-mercaptopurine oxidation catalyzed by the mPOS–PVA–XOD followed the same pathway described for the free enzyme, namely, 6-mercaptopurine → 6-mercapto-8-hydroxypurine → 6-thiouric acid, and no 6-thioxanthine was formed.

Graphical abstractFigure optionsDownload full-size imageDownload high-quality image (104 K)Download as PowerPoint slideHighlights► High specific activity retention (half of the free enzyme). ► Optimal pH and temperature slightly higher than those of the free enzyme. ► No decrease of activity after five reuses and only 17% after ten reuses. ► Apparent Michaelis constant equal to that estimated for free enzyme. ► 6-Mercaptopurine oxidation following the same pathway described for the free enzyme.

Keywords
Immobilization; Magnetic support; Xanthine oxidase; Catalyzed oxidation; 6-Mercaptopurine
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Purines oxidation by immobilized xanthine oxidase on magnetic polysiloxane–polyvinyl alcohol composite
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Publisher
Database: Elsevier - ScienceDirect
Journal: Applied Catalysis A: General - Volume 401, Issues 1–2, 15 July 2011, Pages 210–214
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Catalysis
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Don't Miss Today's Special Offer
Price was $35.95
You save - $31
Price after discount Only $4.95
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Full-text PDF Download
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