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 Alert me to new issues of the journal
Right arrow Add to My Personal Archive
Right arrow Download to citation manager
Right arrowRequest Permissions
Google Scholar
Right arrow Articles by Mikami, B.
Right arrow Articles by Ida, S.
Right arrow Search for Related Content
PubMed
Right arrow Articles by Mikami, B.
Right arrow Articles by Ida, S.
Agricola
Right arrow Articles by Mikami, B.
Right arrow Articles by Ida, S.
Social Bookmarking
Add to CiteULike   Add to Connotea   Add to Del.icio.us  
What's this?

Plant and Cell Physiology, 1986, Vol. 27, No. 6 1013-1021
© 1986

Article

Reversible Inactivation of Ferredoxin-Nitrate Reductase from the Cyanobacterium Plectonema boryanum. The Role of Superoxide Anion and Cyanide

Bunzo Mikami and Shoji Ida1

The Research Institute for Food Science, Kyoto University Uji, Kyoto 611, Japan

1To whom correspondence should be addressed.

Assimilatory nitrate reductase (NR) from the cyanobacterium Plectonema boryanum exhibits both ferredoxin (Fd)- and methyl viologen (MV)-linked activities. Native (Fd-linked) activity was reversibly inactivated by the exposure of a dithionite solution of the enzyme to air, whereas MV-linked activity remained unaffected. Cyanate and azide, competitive inhibitors of NR, suppressed the dithionite-induced inactivation, and the inactivation was specifically prevented by superoxide dismutase (SOD). Xanthine oxidase reaction inactivated Fd-linked activity but not MV-linked activity, and the native activity was protected by SOD and catalase. Photoactivated FAD/ EDTA irreversibly inactivated both Fd- and MV-linked activities, and the former activity was protected by ascorbic acid. Dithionite-inactivated enzyme was restored to its Fd-linked activity when incubated with cyanate or azide in the presence of dithionite or reduced Fd. Cyanide inactivated both Fd- and MV-linked activities when the enzyme was incubated under reducing conditions. The cyanide-inactivated enzyme was also reactivated by cyanate and azide under reducing conditions. It is suggested that superoxide and cyanide act as ligands to the molybdenum center in the reversible inactivation of the native activity of cyanobacterial Fd-NR.

(Received March 3, 1986; Accepted May 30, 1986)
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.