Abstract
A cytoplasmic NADH oxidase (NOX) was purified from a soil bacteria, Brevibacterium sp. KU1309, which is able to grow in the medium containing 2-phenylethanol as the sole source of carbon under an aerobic condition. The enzyme catalyzed the oxidation of NADH to NAD+ involving two-electron reduction of O2 to H2O2. The molecular weight of the enzyme was estimated to be 102 kDa by gel filtration and 57 kDa by SDS-PAGE, which indicates that the NOX was a homodimer consisting of a single subunit. The enzyme was stable up to 70 degrees C at a broad range of pH from 7 to 11. The enzyme activity increased about ten-fold with the addition of ammonium salt, while it was inhibited by Zn2+ (39%), Cu2+ (41%), Hg2+ (72%) and Ag+ (37%). The enzyme acts on NADH, but not on NADPH. The regeneration of NAD+ utilizing this enzyme made selective oxidation of mandelic acid or L: -phenylalanine possible. This thermostable enzyme is expected to be applicable as a useful biocatalyst for NAD+ recycling.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Amino Acid Sequence
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Bacterial Proteins / chemistry*
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Bacterial Proteins / genetics
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Bacterial Proteins / isolation & purification*
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Bacterial Proteins / metabolism
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Brevibacterium / chemistry
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Brevibacterium / enzymology*
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Brevibacterium / genetics
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Brevibacterium / metabolism
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Cholesterol / metabolism
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Enzyme Stability
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Hot Temperature
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Hydrogen Peroxide / metabolism*
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Kinetics
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Molecular Sequence Data
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Multienzyme Complexes / chemistry*
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Multienzyme Complexes / genetics
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Multienzyme Complexes / isolation & purification*
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Multienzyme Complexes / metabolism
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NADH, NADPH Oxidoreductases / chemistry*
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NADH, NADPH Oxidoreductases / genetics
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NADH, NADPH Oxidoreductases / isolation & purification*
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NADH, NADPH Oxidoreductases / metabolism
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Oxidation-Reduction
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Phenylethyl Alcohol / metabolism*
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Sequence Alignment
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Substrate Specificity
Substances
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Bacterial Proteins
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Multienzyme Complexes
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Cholesterol
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Hydrogen Peroxide
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NADH oxidase
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NADH, NADPH Oxidoreductases
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Phenylethyl Alcohol