312 



ELECTRON TRANSPORT 



manner entirely analogous to the effect of high ionic media, preincu- 

 bation of chromatophores in light, but not in the dark, and with an 

 electron donor system completely eliminates induction. These results 

 provide the first indication of a possible coupling of photochemical 

 electron flow to processes occurring during induction. It should be 

 mentioned that media of high ionic strength reversibly suppress 

 photopho spho ry lation . 



5 10 15 



Time, Minutes 



Fig, 5. Effect of sodium dodecyl sulfate (SDS), 0.3 

 mg./ml.on disulfide photoreduction in medium of high 

 ionic strength (// = 2.5, (NH4)2SO^ in tris buffer). 



Finally, additional information about the nature of induction comes 

 from a study of other agents promoting the process in media of high 

 ionic strength. For example, the data in Fig. 5 show that the anionic 

 detergent, sodium dodecyl sulfate (SDS) is a very effective agent for 

 producing an induction period; whereas cationic detergents were not. 

 It should be noted that SDS dissolves chromatophores and destroys the 

 pigment system inmediaof low ionic strength, and that chromatophores 



