Isolation and Some Properties of Cytochrome c Oxidase Purified from a Bisulfite Ion Resistant Thiobacillus ferrooxidans Strain, OK1-50

Kenji Iwahori, Kazuo Kamimura, Tsuyoshi Sugio

Research output: Contribution to journalArticle

22 Citations (Scopus)

Abstract

Sulfite ion (HSO3) is one of the products when elemental sulfur is oxidized by the hydrogen sulfide:ferric ion oxidoreductase of Thiobacillus ferrooxidans AP19-3. Under the conditions in which HSO3 is accumulated in the cells, the iron oxidase of this bacterium was strongly inhibited by HSO3. Since cytochrome c oxidase is one of the most important components of the iron oxidase enzyme system in T. ferrooxidans, effects of HSO3 on cytochrome c oxidase activity were studied with the plasma membranes of HSO3-resistant and -sensitive strains of T. ferrooxidans, OK1-50 and AP19-3. The enzyme activity of AP19-3 compared with OK1-50 was strongly inhibited by HSO3. To investigate the inhibition mechanism of HSO3 in T. ferrooxidans, cytochrome c oxidases were purified from both strains to an electrophoretically homogeneous state. Cytochrome c oxidase activity of a purified OK1-50 enzyme was not inhibited by 5 mM HSO3. In contrast, the same concentration of HSO3 inhibited the enzyme activity of AP19-3 50%, indicating that the cytochrome c oxidase of OK1-50 was more resistant to HSO3 than that of AP19-3. Cytochrome c oxidases purified from both strains were composed of three subunits. However, the molecular weight of the largest subunit differed between OK1-50 and AP19-3. Apparent molecular weights of the three subunits of cytochrome c oxidases were 53,000, 24,000, and 19,000 for strain AP19-3 and 55,000, 24,000, and 19,000 for strain OK1-50, respectively.

Original languageEnglish
Pages (from-to)1081-1086
Number of pages6
JournalBioscience, Biotechnology and Biochemistry
Volume62
Issue number6
DOIs
Publication statusPublished - Jan 1 1998

Keywords

  • Bisulfite ion
  • Cytochrome c oxidase
  • Iron-oxidizing bacterium
  • Resistance
  • Thiobacillus ferrooxidans

ASJC Scopus subject areas

  • Biotechnology
  • Analytical Chemistry
  • Biochemistry
  • Applied Microbiology and Biotechnology
  • Molecular Biology
  • Organic Chemistry

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