172 METABOLISM AND PHYSIOLOGY 



TABLE 3 



Effects of Uncoupling Agents and Inhibitors of Electron Transport 

 on Aerobic Phosphorylation 



The procedure and enzyme used were as described in Table 1. The solutions 

 of inhibitors were made just before use; p-FgCOCCP and 2,4-DNP were dis- 

 solved in excess NaOH, 



oxidase was found to be sensitive to amytal (and the phosphorylation 

 correspondingly so, as shown here). Both DPNH oxidase and phos- 

 phorylation were moderately affectedby high concentrations of cyanide, 

 and aerobic phosphorylation was inhibited by phenazine methyl sulfate. 



DISCUSSION 



The fact that the bulk of the DPNH oxidase of crude dark extracts 

 may be separated from the phosphorylation system does not neces- 

 sarily imply that the two activities were not associated in the cell 

 prior to disruption. Indeed, the nature of the particulates of such ex- 

 tracts is most likely a function of the means used to break the cells. 

 This is exemplified by the experiments of M. Baltscheffsky (9) which 

 demonstrated that the type of abrasive used influenced the amount of 

 "soluble" DPNH oxidase activity obtained in extracts of photosyntheti- 

 cally grown R. rubnim. Furthermore, experience with "chromatophore 

 fractions" in R. nibnim must be cited; all of the pigment of osmotic 

 lysates of lysozyme-treated R. nihnun cells was found to sediment 

 readily in very low centrifugal fields (10), 



