pH profile of cytochrome c-catalyzed tyrosine nitration
Autor: | Kei Takemoto, Masafumi Shibamori, Keiki Ogino, Junna Okuda, Norio Kodama, Yoshiaki Hitomi, Tomoko Takigawa, Yasuhiro Kambayashi, Masayuki Kubo |
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Rok vydání: | 2006 |
Předmět: | |
Zdroj: | Acta Biochimica Polonica. 53:577-584 |
ISSN: | 1734-154X 0001-527X |
Popis: | 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 cytochromec-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 degrees C). The amount of nitrotyrosine formed was the greatest at pH 5. At pH 3, only cytochromec-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. |
Databáze: | OpenAIRE |
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