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Purification and characterization of a nitroreductase from the soil bacterium Streptomyces mirabilis

Paper ID Volume ID Publish Year Pages File Format Full-Text
34564 45034 2012 5 PDF Available
Title
Purification and characterization of a nitroreductase from the soil bacterium Streptomyces mirabilis
Abstract

A NADH-dependent nitroreductase from an efficient nitro-reducing soil bacterium, Streptomyces mirabilis DUT001, was isolated and characterized. The enzyme was purified to near homogeneity using ammonium sulfate precipitation, ion exchange chromatography, and gel filtration chromatography. The native enzyme was estimated by gel filtration to have a molecular weight of 68 kDa, and its subunit molecular weight determined by SDS-PAGE was about 34 kDa, which indicated this enzyme was a dimer. Polycyclic nitroaromatic compounds were preferred substrates for this enzyme. The purified enzyme exhibited maximum activity at pH 7.5 and 40 °C. The addition of various chemicals such as reducing agents, metal ions, and chelating agents, had effects on enzyme activity. Mg2+, Ca2+, Sr2+, and 1% (w/v) Triton X-100 increased activity. However, Hg2+, Co2+, Ni2+, Cu2+, and SDS reduced activity. The maximum reaction rate (Vmax) was 64 μM min−1 mg−1 enzyme and the apparent Michaelis–Menten constants (Km) for 4-nitro-1,8-naphthalic anhydride and NADH were 276 and 29 μM, respectively. Menadione, bimethylenebis, sodium benzoate, and antimycin A were inhibitors of the purified nitroreductase with apparent inhibition constants (Kis) of 20, 36, 44 and 80 μM, respectively.

► A 68 kDa nitroreductase from the strain Streptomyces was isolated and characterized. ► Its preferred substrate is polycyclic nitroaromatic compounds. ► The optimal condition for enzymatic activity is pH 7.5 and 40 °C. ► N-terminus amino acid sequence suggests its a novel nitroreductase.

Keywords
Biotransformation; Nitroreductase; Nitroaromatic compounds; Streptomyces
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Purification and characterization of a nitroreductase from the soil bacterium Streptomyces mirabilis
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Publisher
Database: Elsevier - ScienceDirect
Journal: Process Biochemistry - Volume 47, Issue 5, May 2012, Pages 720–724
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