Skip Navigation

This Article
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Add to My Personal Archive
Right arrow Download to citation manager
Right arrow Request Permissions
Google Scholar
Right arrow Articles by HASHIMOTO, K.
Right arrow Articles by NISHIMURA, M.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by HASHIMOTO, K.
Right arrow Articles by NISHIMURA, M.
Social Bookmarking
Add to CiteULike   Add to Connotea   Add to Del.icio.us  
What's this?

J. Biochem, 1982, Vol. 91, No. 4 1111-1120
© 1982 Japanese Biochemical Society

research-article

Characterization of Electron Donation to Cytochrome c-555 in Chromatium vinosum from Ferrocyanide, Tetramethyl-phenylenediamine and Reduced Dimethylquinone. Effects of Redox Potential, pH and Salt Concentration

Ken HASHIMOTO1, Shigeru ITOH, Ken-ichiro TAKAMIYA and Mitsuo NISHIMURA

Department of Biology, Faculty of Science, Kyushu University 33 Higashi-ku, Fukuoka, Fukuoka 812

1. The dependences of the reduction of femcytochrome c-555 in the reaction center-cytochrome c complex on the redox potential and pH were investigated using N,N,N',N'-tetramethyl-p-phenylenediamine (TMPD), ferrocyanide, and reduced 2,5-dimethyl-p-quinone as electron donors.

2. In the reduction of cytochrome c-555 by TMPD, the unprotonated form was the exclusive electron donor to the cytochrome with a second-order rate constant of l.0x105M–1·s–1.

3. Ferrocyanide reduced cytochrome c-555 slowly with a rate constant of 7.8 x 102 M–1. s–1 at infinite salt concentration. The value of –5.2 x 10–4 elementary charge/ Å2 was estimated as the surface charge density in the vicinity of cytochrome c-555 by analyzing the salt effect on the cytochrome reduction using the Gouy-Chapman theory.

4. The characteristics of the dependences of the reduction of cytochrome c-555 by reduced 2,5-dimethyl-p-quinone on the redox potential and pH were well explained by the redox potential and pH dependences of the formation of the semiquinone. In the neutral-to-alkaline pH range the anionic semiquinone was the main electron- donating species with a second-order rate constant of 6.Ox 107 M–1·s–1.

1Present address: Department of Pathology, The Hahnemann Medical College, Philadelphia, PA 19102, U.S.A.


Add to CiteULike CiteULike   Add to Connotea Connotea   Add to Del.icio.us Del.icio.us    What's this?




Disclaimer: Please note that abstracts for content published before 1996 were created through digital scanning and may therefore not exactly replicate the text of the original print issues. All efforts have been made to ensure accuracy, but the Publisher will not be held responsible for any remaining inaccuracies. If you require any further clarification, please contact our Customer Services Department.