
TY  - JOUR
A1  - Chow, WS 
A1  - Hope, AB 
T1  - Proton Translocation, Electron Transport and Phosphorylation in Isolated Chloroplasts
JF  - Functional Plant Biology
JO  - Functional Plant Biol.
Y1  - 1977
VL  - 4
IS  - 4
SP  - 647
EP  - 665
KW  - 
UR  - https://doi.org/10.1071/PP9770647 
N2  - The steady-state rates of proton translocation (&#934;H) associated with rates of light-induced electron transport (&#934;e) have been studied under a variety of conditions, with and without phosphorylation, in both spinach and pea chloroplasts, and using the absorbance changes of phenol red as a pH indicator. The method is discussed critically and compared with others. Using values of &#934;H estimated from the initial efflux of H+ after continuous illumination for 17 s, it has been found that &#934;H/&#934;e increased to a maximum value of 2 under conditions which enhanced the permeability of membranes to H+ and a second ion. The maximum value of about 2 was observed over the whole pH range for which phenol red can be used as a pH indicator, namely pH 7.0 - 8.7. The stimulation of electron transport by phosphorylation was also studied with a view to enquiring into the ratio &#934;HH/RATP, where &#934;H is the proton flux via an ATPase giving rise to a phosphorylation rate RATP.    A scheme of the pathways of protons in the thylakoid membrane is proposed to account for the evariation of &#934;H/&#934;e under a large range of conditions. This scheme is in line with the 'bobbing up and down' hypothesis for the mechanism of active proton transport in energy-transducing membranes. 
ER  -

