Document Detail

Effect of pyridine homologues on proton flux through the CF0 . CF1 complex and photophosphorylation in chloroplasts.
MedLine Citation:
PMID:  6284734     Owner:  NLM     Status:  MEDLINE    
At concentrations below 1 mM, hydrophobic pyridine homologues decrease the rate of photophosphorylation and light-stimulated hydrolysis of ATP and light-activated exchange of the tightly bound nucleotides in chloroplasts, but increase the rate of the Hill reaction. Unlike uncoupling agents, the presence of the organic base at such low concentrations decreases the rate of light-dependent leakage and has no effect on the efficiency of two-stage photophosphorylation in broken chloroplasts. By assuming that the organic base is bound to independent equivalent sites in the thylakoid membrane, a simple expression can be derived which relates the observed rates of photophosphorylation and light-stimulated hydrolysis of ATP quantitatively to the concentration of the organic base in solution and gives dissociation equilibrium constants which are on the order of the relative hydrophobicities of the pyridine homologues. A possible mechanistic model for the CF0 . CF1 complex is proposed which could serve as the basis for a unified interpretation of the kinetics of proton translocation in illuminated chloroplasts, the steady-state rate of photophosphorylation, the light-stimulated ATPase activity, and the light-activated exchange of tightly bound adenine nucleotides.
Y K Ho; J H Wang
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Publication Detail:
Type:  Journal Article; Research Support, U.S. Gov't, Non-P.H.S.    
Journal Detail:
Title:  Journal of bioenergetics and biomembranes     Volume:  14     ISSN:  0145-479X     ISO Abbreviation:  J. Bioenerg. Biomembr.     Publication Date:  1982 Apr 
Date Detail:
Created Date:  1982-09-10     Completed Date:  1982-09-10     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  7701859     Medline TA:  J Bioenerg Biomembr     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  97-113     Citation Subset:  IM    
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MeSH Terms
Adenine Nucleotides / metabolism
Adenosine Triphosphatases / metabolism*
Chloroplasts / metabolism*,  radiation effects
Electron Transport / drug effects
Photophosphorylation / drug effects*
Plants / metabolism
Proton-Translocating ATPases / metabolism*
Pyridines / pharmacology*
Reg. No./Substance:
0/Adenine Nucleotides; 0/Protons; 0/Pyridines; EC 3.6.1.-/Adenosine Triphosphatases; EC ATPases

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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