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°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.
Original language | English |
---|---|
Pages (from-to) | 71-78 |
Number of pages | 8 |
Journal | Applied Microbiology and Biotechnology |
Volume | 80 |
Issue number | 1 |
DOIs | |
Publication status | Published - 2008 Aug |
Keywords
- Brevibacterium sp.
- Cofactor regeneration
- Hydrogen peroxide
- Molecular oxygen
- NADH oxidase
ASJC Scopus subject areas
- Biotechnology
- Applied Microbiology and Biotechnology