@article{open267,
          volume = {367},
          number = {Pt 1},
           month = {October},
          author = {Radha Chauhan and Shekhar C Mande},
            note = {Copyright of this article belongs to Portland Press.},
           title = {Site-directed mutagenesis reveals a novel catalytic mechanism of Mycobacterium tuberculosis alkylhydroperoxidase C.},
       publisher = {Portland Press},
            year = {2002},
         journal = {The Biochemical journal},
           pages = {255--61},
        keywords = {antioxidant, dithiothreitol oxidation, glutamine synthetase enzyme, metal-catalysed oxidation},
             url = {http://crdd.osdd.net/open/267/},
        abstract = {Mycobacterium tuberculosis alkylhydroperoxidase C (AhpC) belongs to the peroxiredoxin family, but unusually contains three cysteine residues in its active site. It is overexpressed in isoniazid-resistant strains of M. tuberculosis. We demonstrate that AhpC is capable of acting as a general antioxidant by protecting a range of substrates including supercoiled DNA. Active-site Cys to Ala mutants show that all three cysteine residues are important for activity. Cys-61 plays a central role in activity and Cys-174 also appears to be crucial. Interestingly, the C174A mutant is inactive, but double mutant C174/176A shows significant revertant activity. Kinetic parameters indicate that the C176A mutant is active, although much less efficient. We suggest that M. tuberculosis AhpC therefore belongs to a novel peroxiredoxin family and might follow a unique disulphide-relay reaction mechanism.}
}