Characterization of a NADH:dichloroindophenol oxidoreductase from Bacillus subtilis

We expressed and purified an azoreductase homolog, YvaB, from Bacillus subtilis. YvaB was found to have NADH:2,6-dichloroindophenol oxidoreductase activity, as well as azoreductase activity. Purified YvaB was active without FMN, unlike Escherichia coli azoreductase. YvaB was most active at pH 7.5 and 40 degrees C, and was stable up to 55 degrees C after incubation for 30 min. Remarkably, it was stable in the presence of Ag+, and was activated by the addition of non-ionic detergents. Other enzymatic properties of YvaB were also investigated.