Disease relevance of katG

• On the catalase-peroxidase gene, katG, of Mycobacterium leprae and the implications for treatment of leprosy with isoniazid [1].
• The toxicity of the potent tuberculocidal agent, isoniazid, is mediated by the heme-containing enzyme, catalase-peroxidase, encoded by the katG gene [1].

High impact information on katG

• However, unlike that of M. tuberculosis, the katG of M. leprae has been reported to be a pseudogene, implicating that isoniazid, which is activated to a potent tuberculocidal agent by catalase, is unlikely to be of therapeutic benefit to leprosy patients [2].
• As Mycobacterium leprae proliferate inside macrophages, it has been speculated that catalase encoded by katG may protect the bacilli from deleterious effects of peroxide generated from the macrophage and may also play a crucial role in the survival of M. leprae in vivo [2].
• Inactive genes were detected by the polymerase chain reaction in several isolates of M. leprae, of different geographical origins, and attempts to complement an isoniazid-resistant strain of Mycobacterium smegmatis with the katG pseudogene were unsuccessful [1].

Biological context of katG

• Although isoniazid has been used for the treatment of leprosy, it is shown here that the katG gene of Mycobacterium leprae is a pseudogene, which has probably been inactivated by multiple mutations [1].

References