@article{8507,
  keywords = {Animals, Bacterial Proteins, Hemoglobins, Humans, Hydrogen Peroxide, Inactivation, Metabolic, leprosy, Mycobacterium leprae, Peroxynitrous Acid, Truncated Hemoglobins},
  author = {Ascenzi P and De Marinis E and Visca P and Ciaccio C and Coletta M},
  title = {Peroxynitrite detoxification by ferryl Mycobacterium leprae truncated hemoglobin O.},
  abstract = {<p>During infection, Mycobacterium leprae is faced with the host macrophagic environment limiting the growth of the bacilli. However, (pseudo-)enzymatic detoxification systems, including truncated hemoglobin O (Ml-trHbO), could allow this mycobacterium to persist in vivo. Here, kinetics of peroxynitrite (ONOOH/ONOO(-)) detoxification by ferryl Ml-trHbO (Ml-trHbO-Fe(IV)=O), obtained by treatment with H(2)O(2), is reported. Values of the second-order rate constant for peroxynitrite detoxification by Ml-trHbO-Fe(IV)=O (i.e., of Ml-trHbO-Fe(III) formation; k(on)), at pH 7.2 and 22.0 degrees C, are 1.5x10(4) M(-1) s(-1), and 2.2x10(4) M(-1) s(-1), in the absence of and presence of physiological levels of CO(2) (approximately 1.2x10(-3) M), respectively. Values of k(on) increase on decreasing pH with a pK(a) value of 6.7, this suggests that ONOOH reacts preferentially with Ml-trHbO-Fe(IV)=O. In turn, peroxynitrite acts as an antioxidant of Ml-trHbO-Fe(IV)=O, which could be responsible for the oxidative damage of the mycobacterium. As a whole, Ml-trHbO can undertake within the same cycle H(2)O(2) and peroxynitrite detoxification.</p>},
  year = {2009},
  journal = {Biochemical and biophysical research communications},
  volume = {380},
  pages = {392-6},
  month = {2009 Mar 06},
  issn = {1090-2104},
  doi = {10.1016/j.bbrc.2009.01.088},
  language = {eng},
}