508 LIGHT AND LIFE 



TABLE 3 



Effect of Inhibitors on Photophosphorylation by Chromatium Particles 



(Ogata, Nozaki, and Arnon, 115) 



Each vessel contained, in a final volume of 3.0 ml, cell-free preparation (PS) con- 

 taining 2 mg bacteriochlorophyll and the following, in micromoles: Tris buffer, 

 pH 7.8, 80; MgCl,, 5; K.H^'TO^, 15; ADP, IT); vitamin K., (2-melhyl-I,4-naphtho- 

 quinone) 0.3; and phcnazine methosulfate, 0.1. Inhibitors were added as indicated. 

 Other conditions were the same as those described for Table 2. 



tion by Chromatium particles was resistant to inhibition by dinitro- 

 phenol and o-phenanthroline, as was also the case with vitamin K 

 and phenazine methosulfate type photophosphorylation in chloro- 

 plasts. These inhibitor effects for Chromatium are similar to those re- 

 ported for R. rub nan (49, 59) . 



Table 3 shows that photosynthetic phosphorylation by Chromatin?!! 

 particles also resembled that of chloroplasts in its resistance to grami- 

 cidin and antimycin A [when phenazine methosulfate was present in 

 the reaction mixture (cf. 59) ] and its sensitivity to p-chloromercuri- 

 benzoate (cf. 172). However, unlike chloroplasts (12, 172), photo- 

 phosphorylation by Chromatium particles was, under our experi- 

 mental conditions, resistant to inhibition by methylene blue (cf. 59) . 



8. The Electron Flow Mechanism of Photosynthetic 



Phosphorylation 



Photosynthetic phosphorylation has provided direct experimental 

 evidence for the view that the key event in photosynthesis, the con- 

 version of light into chemical energy, is independent of the classical 

 manifestations of this process in green j^lants: oxygen evolution and 

 CO2 reduction. 11 it is accepted that photosynthetic phosphorylation 

 represents the simplest common denominator of photosynthesis in 

 green plants and bacteria, then a mechanism for this process would 

 be expected to provide a basic pattern for the conversion of light into 

 chemical energy. The salient facts which must be explained are that 



