NBME Answers : Block 2 : #17 = A 6-year-old girl is admitted to the hospital ...

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submitted by mdmofongo(0),

Myeloperoxidase is the only one actually involved in making free radicals. Catalase makes H2O2 into water, Superoxide dismutase eliminates oxygen radicals, LDH makes lactate (no role in bacterial killing), and NO synthase, makes NO.

b1ackcoffee I thought SOD also comes (second) after pathway (making h2o2) to make HO—Cl +

mdmofongo Now that I took a look at the pathway again you are right. Knowing this I’d say that free radicals of O2 still have a chance to cause some damage, as where Hydrogen peroxide just serves as a intermediate for free radical formation. Thus SOD deficiency leaves some bactericidal action but MPO leaves none? +