* M/50 concentration used. No inhibition of the cytochrome-oxidase system with 

 M/50 p-phenylenediamine results with any of the split products at concentrations of 

 5X10-*M. 



t System: washed yeast; compounds at a concentration of 5X10"'* M. 



t System: rat liver slices, 5-hour experiment; compounds at a concentration of 

 1X10-3 M. 



** System: rat liver brei, 2-hoiu- experiment; compounds at a concentration of 

 5X10-«M. 



249 



