Affordable Access

Publisher Website

Uncoupler-dependent decrease in midpoint potential of the chloroplast cytochromeb6

Authors
Journal
Biochimica et Biophysica Acta (BBA) - Bioenergetics
0005-2728
Publisher
Elsevier
Publication Date
Volume
325
Issue
2
Identifiers
DOI: 10.1016/0005-2728(73)90103-5

Abstract

Abstract 1. The midpoint potential of cytochrome b 6 in freshly prepared coupled chloroplasts is approximately +5 mV and the slope of the titration curve is characteristic of a two-electron transition. Subsequent titrations performed one-half hour or more after chloroplast preparation show a slight negative shift of the midpoint potential and a one-electron slope. 2. Titrations of cytochrome b 6 in the presence of carbonylcyanide- p-trifluoromethoxyphenylhydrazone (FCCP) or NH 4Cl show the midpoint potential of approximately half the b 6 complement negatively shifted to about −140 mV. 3. Brief exposure of the chloroplasts to NH 4Cl and actinic illumination under typical uncoupling conditions with controlled potential conditions causes a shift in oxidation state consistent with a lowering of the average midpoint potential to about −100 mV. It is concluded that the midpoint potential of at least half the cytochrome b 6 undergoes a negatively directed shift of 100–150 mV under uncoupling conditions in the presence of NH 4Cl and FCCP.

There are no comments yet on this publication. Be the first to share your thoughts.

Statistics

Seen <100 times
0 Comments

More articles like this

Uncoupler-dependent decrease in midpoint potential...

on Biochimica et Biophysica Acta Nov 22, 1973

The pH dependence of the redox midpoint potential...

on Biochimica et Biophysica Acta... Jan 01, 1992

The pH dependence of the redox midpoint potential...

on Biochimica et Biophysica Acta... Jan 01, 1992
More articles like this..