
TY  - JOUR
A1  - Hope, AB 
A1  - Doherty, G 
A1  - Stainer, P 
T1  - Proton Motive Force and Phosphorylation Potential in Thylakoids
JF  - Functional Plant Biology
JO  - Functional Plant Biol.
Y1  - 1985
VL  - 12
IS  - 1
SP  - 21
EP  - 26
KW  - 
UR  - https://doi.org/10.1071/PP9850021 
N2  - The relationship between phosphorylation potential and the transthylakoid pH difference (&#916;pH) was explored in class C pea chloroplasts under two conditions: (a) in the light, in a steady state following photophosphorylation, where &#916;pH was varied with addition of nigericin, and (b) in the dark after a light period in the presence of dithioerythritol to promote &#916;TP-hydrolase activity. In experiments of type (b), the phosphorylation potential was varied through the concentrations of adenylates. In both conditions there was a correlation between the phosphorylation potential and &#916;pH. The slope of the relationship between the two in the light was taken as giving the product n.q of the mechanistic stoichiometry, n with q, the degree of coupling of the ATP-synthetase reaction with the proton flux. This product was 1.9 ± 0.1, implying n=2 if q=0.95, or n=3 if q=0.66. The data from both types of experiment required a transthylakoid potential difference of up to + 155 mV for the phosphorylation potential to be poised against the proton motive force as in a macrochemiosmotic theory. 
ER  -

