pH profile of cytochrome c-catalyzed tyrosine nitration

Yasuhiro Kambayashi, Yoshiaki Hitomi, Norio Kodama, Masayuki Kubo, Junna Okuda, Kei Takemoto, Masafumi Shibamori, Tomoko Takigawa, Keiki Ogino

Research output: Contribution to journalArticlepeer-review

10 Citations (Scopus)


In the present study, we investigated how cytochrome c catalyzed the nitration of tyrosine at various pHs. The cytochrome c-catalyzed nitration of tyrosine occurred in proportion to the concentration of hydrogen peroxide, nitrite or cytochrome c. The cytochrome c-catalyzed nitration of tyrosine was inhibited by catalase, sodium azide, cystein, and uric acid. These results show that the cytochrome c-catalyzed nitrotyrosine formation was due to peroxidase activity. The rate constant between cytochrome c and hydrogen peroxide within the pH range of 3-8 was the largest at pH 6 (37°C). The amount of nitrotyrosine formed was the greatest at pH 5. At pH 3, only cytochrome c-independent nitration of tyrosine occurred in the presence of nitrite. At this pH, the UV as well as visible spectrum of cytochrome c was changed by nitrite, even in the presence of hydrogen peroxide, probably via the formation of a heme iron-nitric oxide complex. Due to this change, the peroxidase activity of cytochrome c was lost.

Original languageEnglish
Pages (from-to)577-584
Number of pages8
JournalActa Biochimica Polonica
Issue number3
Publication statusPublished - 2006


  • Cytochrome c
  • Nitrite
  • Nitrotyrosine
  • Pseudo-peroxidase
  • pH

ASJC Scopus subject areas

  • Biochemistry, Genetics and Molecular Biology(all)


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