Superoxide dismutase enhances the toxicity of 3-hydroxyanthranilic acid to bacteria.

Cu,Zn.superoxide dismutase (SOD) enhanced the toxicity of 3-hydroxyanthranilic acid (3-HAT) to Salmonella typhimurium strain TA 102, evaluated as ability to form colonies. MnSOD showed the same effect. Inactivated Cu.ZnSOD had no effect. SODs accelerated the oxidation of 3-HAT, but inactivated Cu.ZnSOD caused little acceleration. It is proposed that the acceleration of 3-HAT oxidation leads to the enhancement of the 3-HAT toxicity. Catalase protected the bacteria from the toxicity of 3-HAT enhanced by Cu,ZnSOD, indicating that hydrogen peroxide generated in the oxidation of 3-HAT is involved in the toxicity. SODs accelerate the oxidation of 3-HAT and generate more hydrogen peroxide, that causes the enhancement of the 3-HAT toxicity to the bacteria. However, hydrogen peroxide alone was not so toxic. Hydrogen peroxide with 3-HAT was more toxic to the bacteria.