Study of Ferredoxin and Flavodoxin From Tobacco Leaves and Roots Under Normal and Iron-Stressed Conditions

Author

• I-Jen Huang, Utah State University

Date of Award:

5-1991

Document Type:

Thesis

Degree Name:

Master of Science (MS)

Department:

Biology

Committee Chair(s)

Gene Miller

Committee

Gene Miller

Committee

George Welkie

Committee

Larry Rupp

Abstract

I purified tobacco leaf ferredoxin from normal and iron-stressed leaves. The oxidized form of ferredoxin from normal leaves had absorption maxima at 268, 327, and 422 nm and a shoulder at 463 nm. The oxidized form of ferredoxin from iron-stressed leaves had absorption maxima at 268 and 329 nm but no absorption maxima in the 400-nm range. Higher ferredoxin content was found with higher chlorophyll content in leaves of the same age.

A protein in tobacco root extract was isolated and found to serve as an electron carrier for ferredoxin-requiring nitrite reduction. This protein had a molecular weight and antigenic properties very similar to tobacco leaf ferredoxin and commercial spinach ferredoxin. Unlike ferredoxin, this protein did not have electron-carrying activity in the NADP⁺ photoreduction system of chloroplasts.

Flavodoxin, a flavin protein that replaces ferredoxin in bacteria and algae under conditions of insufficient iron and that serves as an electron carrier in nitrite reduction and in NADP⁺ photoreduction, was not found in iron-deficient tobacco leaves and roots after using the same isolation techniques as those described and used for effective purification of flavodoxin from Clostridium pasteurianum.

Recommended Citation

Huang, I-Jen, "Study of Ferredoxin and Flavodoxin From Tobacco Leaves and Roots Under Normal and Iron-Stressed Conditions" (1991). All Graduate Theses and Dissertations, Spring 1920 to Summer 2023. 9083.
https://digitalcommons.usu.edu/etd/9083