Premium
KatG from Salmonella Typhimurium is a peroxynitritase
Author(s) -
McLean Samantha,
Bowman Lesley A.H.,
Poole Robert K.
Publication year - 2010
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/j.febslet.2010.03.029
Subject(s) - peroxynitrite , salmonella , chemistry , microbiology and biotechnology , peroxidase , oxidative phosphorylation , catalase , bacteria , mycobacterium tuberculosis , enzyme , biochemistry , biology , tuberculosis , superoxide , medicine , pathology , genetics
Pathogenic bacteria elicit protective responses to oxidative and nitrosative stresses. Although such responses are generally distinct, it was recently reported in Mycobacterium tuberculosis that catalase–peroxidase (KatG), a classical defence against peroxides, also exhibits peroxynitritase activity. Here, the katG gene from Salmonella Typhimurium was cloned and protein purified and characterised. An increase in the rate of decomposition of peroxynitrite was observed for KatG from the enterobacterium with a second‐order rate constant of 4.2 × 10 4 M −1 s −1 at pH 7.4, 25 °C. This enzyme was able to reduce dihydrorhodamine oxidation by peroxynitrite to ∼83%. Given the peroxynitritase activity demonstrated here it is likely that KatG may play a wider role in the detoxification of oxidative stresses than previously thought.