54 A New Function of " Peroxidase" 



ever (all other conditions being eqiial), one repeats the second ex- 

 periment (2), but adds to the ammoniacal Solution of orcin a siiitable 

 amount of peroxidase, the transformation into orcein takcs place 

 very rapidly and is quite advanced in four or five days^ Compar- 

 ing the coloration intensities of products 2 and 4, one sees that in 

 five days 4 contains more than twice as mtich orcein as 2. This 

 gain is due to the action of the peroxidase. By boiling the perox- 

 idase Solution for f rom 5 to 6 minutes, before adding it to the ammo- 

 niacal Solution of orcin in experiment 4, there is no acceleration in 

 the formation of orcein, evidently because the peroxidase, as the 

 active agent in the transformation, is thus destroyed. 



In Order to determine the rate of oxidation in the different ex- 

 periments, I measured the volumes of absorbed oxygen. In experi- 

 ment 2, eight to nine times more oxygen was absorbed than in i, 

 in the course of 48 hours. In experiments 3 and 4 there was a 

 similar difference but, because of the presence of peroxidase, the 

 proportions of absorbed oxygen were larger. 



Without discussing the nature of the combined action of am- 

 monia, oxygen, and peroxidase upon orcin, we may conclude that 

 in dilute Solutions of orcin, slozv oxidation by ammonia is the pri- 

 mary condition for the formation of orcein. If, however, to this 

 condition is added the accelerating influence of peroxidase, the 

 action is directed toward formation of coloring matter rather than 

 toward increased absorption of oxygen. These facts may possibly 

 be helpful in the commercial preparation of orseille. 



Paris, France. 



* My first and third experiments could easily be performed in flasks with flat 

 bottoms. A small test tube would be satisfactory for experiments 2 and 4. 

 The proportions of materials indicated below are well adapted for the purposes 

 of the experiments : 



^ , ( 2 c.c. of 2.8 per Cent. Solution of ) tnm x j -.i 



For I and 2 < , , , ^j^ > Diluted with water to 3.5 c.c. 



( orcm and 50 mg. of NH3 ) 



2 c.c. of 2.8 per Cent. Solution of 

 For 3 and 4 ■{ orcin, 50 mg. of NH3 and \- Diluted with water to 3.5 c.c. 



I c.c. of active peroxidase Solution 



