Quinone reductase that provides resistance to thiol-specific stress caused by electrophilic quinones. Also exhibits azoreductase activity. Catalyzes the reductive cleavage of the azo bond in aromatic azo compounds to the corresponding amines. 2 a quinone + H(+) + NADH = 2 a 1,4-benzosemiquinone + NAD(+) anthranilate + N,N-dimethyl-1,4-phenylenediamine + 2 NAD(+) = 2-(4-dimethylaminophenyl)diazenylbenzoate + 2 H(+) + 2 NADH Binds 1 FMN per subunit. Homodimer. Belongs to the azoreductase type 1 family.