Cm. Gomes et M. Teixeira, THE NADH OXIDASE FROM THE THERMOACIDOPHILIC ARCHAEA ACIDIANUS-AMBIVALENS - ISOLATION AND PHYSICOCHEMICAL CHARACTERIZATION, Biochemical and biophysical research communications, 243(2), 1998, pp. 412-415
A flavoprotein with NADH oxidising activity (NADH: acceptor oxidoreduc
tase) was isolated from the soluble fraction of the thermoacidophilic
archaea Acidianus ambivalens. The protein is a monomer with a molecula
r mass of 76 kDa and contains FAD as single cofactor. Its activity as
NADH:O-2 oxidoreductase is FAD, but not FMN, dependent and yields hydr
ogen peroxide as the reaction product. The activity decreases with pH
in the range 4.5 to 9.8, and increases with the temperature, as tested
from 30 degrees to 60 degrees C. As elicited by EPR, the purified enz
yme also acts as an NADH:ferredoxin oxidoreductase. These features are
discussed in light of the possible involvement of this protein in the
metabolism of this archaea. (C) 1998 Academic Press.