Which enzyme resists host cell oxidation in Mycobacterium tuberculosis?

Which enzyme resists host cell oxidation in Mycobacterium tuberculosis?

• A. Superoxide dismutase
• B. Urease
• C. Beta-lactamase
• D. Catalase-peroxidase (KatG)

Answer: (D)

Macrophages kill bacteria by generating reactive oxygen species as part of the oxidative burst. Mycobacterium tuberculosis defends itself with catalase-peroxidase KatG, which detoxifies hydrogen peroxide and organic peroxides, helping the bacterium survive the host’s oxidative attack. This direct breakdown of oxidative agents is the key way MTB resists the macrophage’s killing mechanism. Urease and beta-lactamase aren’t involved in this oxidative detoxification. Superoxide dismutase also helps manage oxidative stress, but KatG’s specific role in neutralizing hydrogen peroxide makes it the best fit for resisting host cell oxidation in this organism.

Macrophages kill bacteria by generating reactive oxygen species as part of the oxidative burst. Mycobacterium tuberculosis defends itself with catalase-peroxidase KatG, which detoxifies hydrogen peroxide and organic peroxides, helping the bacterium survive the host’s oxidative attack. This direct breakdown of oxidative agents is the key way MTB resists the macrophage’s killing mechanism. Urease and beta-lactamase aren’t involved in this oxidative detoxification. Superoxide dismutase also helps manage oxidative stress, but KatG’s specific role in neutralizing hydrogen peroxide makes it the best fit for resisting host cell oxidation in this organism.