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UNCOUPLING OF PHOTOPHOSPHORYLATION BY NITROGENOUS BASES. NO CORRELATION Ofb UNCOUPLING WITH pK b and PARTITION COEFFICIENT
Author(s) -
LotinaHennsen Blas,
King Beatriz,
Albores Martha,
Pozas Rocío
Publication year - 1987
Publication title -
photochemistry and photobiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.818
H-Index - 131
eISSN - 1751-1097
pISSN - 0031-8655
DOI - 10.1111/j.1751-1097.1987.tb04768.x
Subject(s) - photophosphorylation , acetamide , chemistry , electron transport chain , steric effects , atp synthase , partition coefficient , chloroplast , uncoupling agents , protonation , atpase , biochemistry , stereochemistry , mitochondrion , chromatography , organic chemistry , enzyme , gene , ion
Abstract Twenty six nitrogenous compounds were tested for uncoupling activity from water to methylviologen in spinach chloroplasts. No correlation was found between photophosphorylation and pK b or partition coefficient. Thus basic strength is not related with uncoupling phenomena, suggesting that nitrogenous bases are not protonated during uncoupling. Steric effect is also unimportant for uncoupling. New discovered uncouplers were acetamide, hexylamide and trichloroacetamide, which are all very efficient uncouplers. Acetamide accelerates electron transport and decreases ATP synthesis. However, it increases net proton uptake at low concentration, and collapses proton gradient at high concentration. 1,12 Diaminododecane is also a very efficient uncoupler'but it does not have any relationship with other diamines tested; it causes reversible shrinkage to the chloroplast, which suggests that it is not a detergent type of uncoupler.