THE SUPPOSED ACTION OF POTASSIUM PERMANGA- 

 NATE WITH PLANT PEROXIDASES 



Herbert H. Bunzell and Heinrich Hasselbring 



Reed 1 has recently reported experiments which he believes 

 throw a new light on the mechanism of oxidation in living tissues. 

 The experiments relate to the reactions involved in the process of 

 oxidation by means of peroxidases. To a horseradish extract, which 

 in itself was incapable of bringing about the oxidation of potassium 

 iodide or of gum guaiac, he added concentrated potassium per- 

 manganate solution until the permanganate was no longer reduced. 

 He then added a small excess of horseradish extract to reduce any 

 free permanganate present. On filtration a clear, rather deep 

 yellow solution was obtained, which, when mixed with solutions 

 of potassium iodide, gum guaiac, or pyrogallol, caused rapid 

 oxidations of those substances. Reed's interpretation of these 

 experiments is that the peroxidase of the horseradish extract com- 

 bines with oxygen from the permanganate, thus forming a new 

 compound which readily gives up oxygen to other compounds. 

 He concludes, therefore, that in oxidation processes catalyzed by 

 peroxidases two reactions are involved: first, a combination of the 

 peroxidase with oxygen from substances acting as oxygenases; 

 and second, a transfer of this oxygen to the substances oxidized by 

 means of peroxidases. Thus he believes the mechanism of oxi- 

 dation in living tissues is explained. 



Contrary to Reed's belief, this interpretation throws no new 



* 



mechani 



Traube 



Kastle and Loevenhart. Moreover, since manganese com- 



themselves 



mixtures 



with wjiich he worked to peroxidase activated by ox 

 postassium permanganate is at least open to questi 



x Reed, G. B., The mode of action of plant peroxidases. Box. 

 1916. 



225] 



That the 



[Botanical Gazette, vol. 63 



