PHOTOPHOSPHORYLATION IN RHODOSPIRILLUM 

 RUBRUM. ABOUT THE ELECTRON TRANSPORT 

 CHAIN AND THE PHOSPHORYLATION 

 REACTIONS 



MARGaRETA BALTSCHEFFSKY and HERRICK BALTSCHEFFSKY 



Wemier-Gren Institute caul Depcirtnieiit of Biochemistry 

 University of Stocliholm, Sweden 



INTRODUCTION 



It has long been recognized that the phosphorylation reactions in the 

 light-induced production of ATP in photosynthesis are closely linked 

 to electron transport. The various results in the field of electron 

 transport and phosphorylation which led to a realization of this cir- 

 cumstance caused what may be regarded as an intrusion into the area 

 of the classical union between photochemistry and carbohydrate metab- 

 olism in photosynthesis. Today many agree that the following light- 

 induced sequence of events may occur in all photosynthetic organisms: 



1. The photochemical reactions. 



2. The electron transport- linked photophosphorylation, 



3. The assimilation of carbon dioxide. 



In this presentation some aspects of the electron transport and phos- 

 phorylation reactions of photophosphorylation in isolated chromato- 

 phores from the photosynthetic bacterium Rho do spirillum rubnimvAW 

 be discussed in general and, where it appears to be justified, in spe- 

 cific terms. 



ABOUT THE ELECTRON TRANSPORT CHAIN 



High rates of cyclic photophosphorylation can be obtained in isolated 

 bacterial chromatophores without any added electron carriers. In con- 

 trast to isolated chloroplasts from green plants, where so far the 

 cyclic process has been found to occur only in the presence of such 

 added compounds, the bacterial systehi is thus particularly suitable 

 for studies of the physiological electron carriers and carrier sequences 

 which participate in the cyclic photophosphorylation process, 



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