118 THE BACTERIAL PHOTOCHEMICAL APPARATUS 



e 



400 



600 



800 m/j 



Fig. 3. 



-Absorption spectrum of bacteriochlorophyll in 



dry ethyl ether. 



Absorption spectrum of bacteriopheophytin in dry ethyl 



ether. 



We have tested the B794 particles for their capacity to photoreduce 

 pyridine nucleotides but with negative results thus far. It would, how- 

 ever, be most surprising if these particles did show any capacity to 

 carry out partial photosynthetic reactions in the absence of true 

 bacteriochlorophyll. 



CONCLUSIONS 



A particulate material which has only one red absorption peak at 

 794 Ytiju has been isolated from actively growing cultures of R. rnbnim. 

 The pigment responsible for the absorption peak has been character- 

 ized as bacteriopheophytin on the basis of its spectral characteristics. 



