Thus, the NADPH-dependent disulfide reductase activity of MtbFHb can participate in conjunction with thioredoxin reductase and Mtr to create a robust antioxidant system that can play a vital role in protecting the viability and maintenance of redox balance by reduction of oxidized mycothiol and its recycling during intracellular infection when Mtb gets exposed to copious amounts of reactive oxygen and nitrogen species. The gene discussed is MTR; the disease is infection.