On the Nature of Oxidases. 



By 

 K. Asö, Tokyo. 



In a former article^) I had shown tliat the liberation of 

 iodine from potassinm iodid by certain plantjiüces does not go 

 parallel witli the blne guaiac reaetion, as Bach had supposed 

 and that in one case at least, it was positively shown that 

 the liberation of iodine was due to» traces of nitrous acid. 

 That article had induced Chodat and Bach-) to some re- 

 niarks Avhich led me to make some fm'ther trials. These show 

 that the view of Chodat and Bach cannot be generally sus- 

 tained. 



In the first place I nmst adhere to my view that there is 

 no parallelism between the iodine liberation and the giiaiac re- 

 aetion.-^) In the second place I am convinced contrary to the 

 opinion of Chodat and Bach, that the guaiac reaetion upon 

 peroxides is not so sensitive as the liberation of iodine by 

 peroxids. 



In Order to prove this latter assertion the following Obser- 

 vation was made. The common para-aldehyde of commerce has 

 generally an acid reaetion and yields with potassiumiodid-starch 

 very soon an intense blue reaetion due to the liberation of iodine. 

 I entertained the supposition that this reaetion is not caused by 

 the pure para-aldehyde, but by an admixture of an organic per- 

 oxid, very probably by the acetylhydroperoxid. ^) Similar per- 

 oxids have been observed as a result of autoxidation of other 

 aldehydes and also the common ether forms after long contact 

 with the air, an organic peroxid, which sometimes even caused 

 explosions in distilling such an old ether to the last drop. 



I shook therefore about 20 c. c. of commercial para-alde- 

 hyde, with an equal volume of 10% sodium carbonate Solution 



1) Beihefte. Bot. Centr.-Blt. XI. Heft 1. ..Which Compound in certain 

 plantjuices can liberate iodine from potassium iodid ?- 



2) Berichte d. d. ehem. Ges. 1994. Heft 1. 



3) This view is also entertained by Raudnitz. (Monatschrift für 

 Kinderheilkunde. II. Heft 8.) 



<) Page, R. H. (Amer. Pat.) mentioned in the Chemiker-Ztg. Benzal- 

 dehyde (commercial) produced also the iodine reaetion in traces. 



Beihefte Bot. Centralbl. Bd. XVIU. Abt. I. Heft 3. 22 



