Catalyzes the oxidative ring opening of 3-hydroxyanthranilate to 2-amino-3-carboxymuconate semialdehyde, which spontaneously cyclizes to quinolinate. 3-hydroxyanthranilate + O2 = (2Z,4Z)-2-amino-3-carboxymuconate 6-semialdehyde Binds 2 Fe(2+) ions per subunit. Inhibited by 4-chloro-3-hydroxyanthranilate. Mechanism of inactivation involves the oxidation of the catalytic active site Fe(2+) to the catalytically inactive Fe(3+) oxidation state, superoxide production, and formation of two disulfide bonds between Cys-125 and Cys-128, and Cys-162 and Cys-165. Enzyme can be reactivated under reducing conditions. Cofactor biosynthesis; NAD(+) biosynthesis; quinolinate from L-kynurenine: step 3/3. Homodimer. Belongs to the 3-HAO family.