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Effect of changing the nanoscale environment on activity and stability of nitrate reductase

Paper ID Volume ID Publish Year Pages File Format Full-Text
16784 42612 2016 11 PDF Available
Title
Effect of changing the nanoscale environment on activity and stability of nitrate reductase
Abstract

•Nitrate reductase (NR) covalently immobilized onto epoxy affixed Fe3O4 and ZnO nanoparticles.•High immobilization efficiency with decreased Km values was achieved.•Storage and thermal stabilities improved substantially after immobilization.•Nitrate determination using immobilized NR produced reliable data.

Nitrate reductase (NR) is employed for fabrication of nitrate sensing devices in which the enzyme in immobilized form is used to catalyze the conversion of nitrate to nitrite in the presence of a suitable cofactor. So far, instability of immobilized NR due to the use of inappropriate immobilization matrices has limited the practical applications of these devices. Present study is an attempt to improve the kinetic properties and stability of NR using nanoscale iron oxide (nFe3O4) and zinc oxide (nZnO) particles. The desired nanoparticles were synthesized, surface functionalized, characterized and affixed onto the epoxy resin to yield two nanocomposite supports (epoxy/nFe3O4 and epoxy/nZnO) for immobilizing NR. Epoxy/nFe3O4 and epoxy/nZnO support could load as much as 35.8 ± 0.01 and 33.20 ± 0.01 μg/cm2 of NR with retention of about 93.72 ± 0.50 and 84.81 ± 0.80% of its initial activity respectively. Changes in surface morphology and chemical bonding structure of both the nanocomposite supports after addition of NR were confirmed by scanning electron microscopy (SEM) and fourier transform infrared spectroscopy (FTIR). Optimum working conditions of pH, temperature and substrate concentration were ascertained for free as well as immobilized NR preparations. Further, storage stability at 4 °C and thermal stability between 25–50 °C were determined for all the NR preparations. Analytical applications of immobilized NR for determination of soil and water nitrates along with reusability data has been included to make sure the usefulness of the procedure.

Keywords
Nitrate reductase; Zinc oxide; Iron oxide; Nanoparticles; Immobilization; Nitrate determination
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Effect of changing the nanoscale environment on activity and stability of nitrate reductase
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Publisher
Database: Elsevier - ScienceDirect
Journal: Enzyme and Microbial Technology - Volume 89, July 2016, Pages 52–62
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Bioengineering
Get Full-Text Now
Don't Miss Today's Special Offer
Price was $35.95
You save - $31
Price after discount Only $4.95
100% Money Back Guarantee
Full-text PDF Download
Online Support
Any Questions? feel free to contact us