Thiol-specific peroxidase that catalyzes the reduction of hydrogen peroxide and organic hydroperoxides to water and alcohols, respectively. Plays a role in cell protection against oxidative stress by detoxifying peroxides. Together with AhpD, DlaT and Lpd, constitutes an NADH-dependent peroxidase active against hydrogen and alkyl peroxides as well as serving as a peroxynitrite reductase, thus protecting the bacterium against reactive nitrogen intermediates and oxidative stress generated by the host immune system. Does not however seem to play a role in detoxification of isoniazid. (R)-N(6)-dihydrolipoyl-L-lysyl-[lipoyl-carrier protein] + a hydroperoxide = (R)-N(6)-lipoyl-L-lysyl-[lipoyl-carrier protein] + an alcohol + H2O kcat is 0.6 sec(-1) with tert-butyl hydroperoxide as substrate and AhpD as reductant and 0.1 sec(-1) with tert-butyl hydroperoxide as substrate and TrxC as reductant. Homodimer; disulfide-linked, upon oxidation. 6 homodimers assemble to form a ring-like dodecamer (PubMed:11171096, PubMed:15886207). Identified in a complex with AhpD, DlaT and Lpd (PubMed:11799204). Induced in isoniazid (INH)-resistant, KatG-deficient strains as well as in INH-sensitive strains when challenged with the drug. Increased expression in these strains probably compensates for loss of katG activity in detoxification of organic peroxides. A possible member of the dormancy regulon. Induced in response to reduced oxygen tension (hypoxia). It is hoped that this regulon will give insight into the latent, or dormant phase of infection. The active site is a conserved redox-active cysteine residue, the peroxidatic cysteine (C(P)), which makes the nucleophilic attack on the peroxide substrate. The peroxide oxidizes the C(P)-SH to cysteine sulfenic acid (C(P)-SOH), which then reacts with another cysteine residue, the resolving cysteine (C(R)), to form a disulfide bridge. The disulfide is subsequently reduced by an appropriate electron donor to complete the catalytic cycle. In this typical 2-Cys peroxiredoxin, C(R) is provided by the other dimeric subunit to form an intersubunit disulfide (PubMed:15178486, PubMed:15886207). The disulfide can subsequently be reduced through a mixed disulfide with the C-terminal cysteine of AhpD, resolved by its second cysteine (PubMed:15178486) or by thioredoxin (TrxC) (PubMed:14871480). Belongs to the peroxiredoxin family. AhpC/Prx1 subfamily.