+0.05 - 



0.25 - 



0.2 0.4 0.6 0.8 



M/L of Nitrogenous Substance 



Figure 3. The oxidation-reduction potentials of hemin and of some of its hemo- 

 chromogens. The influences of the concentration of the following nitrogenous sub- 

 stances : (i) cyanide-hemochromogen ; (2) pilocarpine-hemochromogen ; (3) histidine 

 hemochromogen ; (4) a-picoline-hemochromogen ; (5) pyridine-hemochromogen ; (6) 

 nicotine-hemochromogen. From Barron, /. Biol. Chem., 121, 285, 1937. 



