1919] 



SCHMITZ AND ZELLER — ENZYME ACTION IN CERTAIN FUNGI 197 



standard iodine solution. The results show the presence of 

 tannase in Polyporus lucidus and Daedalea confragosa but none 

 was detected in Armillaria mellea. This fact seems peculiar, 

 since the rhizomorphs of Armillaria mellea are usually found next 

 to the inner bark of the woody tissues where the tannin is usually 

 present in the greatest amount for the specific host. The fact 

 that the fungi from which the fungous meal was made were 

 grown on carrot may have had some influence on the production 

 of tannase in this particular instance- 



Amidase and Urease 



The presence of the enzymes which split amino acids and urea 

 into ammonia and hydroxy acids was demonstrated by using 

 such substrates as asparagin, acetamid, and urea. The usual 

 Folin method of determining the presence of ammonia is such a 

 time-consuming procedure that a new method was devised 

 involving the indicator method of determining the hydrogen ion 

 concentration of solutions. In brief, the method employed is as 

 follows : 



The substrate and fungous meal in the desired proportions 

 were placed in wash bottles, the inlets and outlets of which were 

 sealed with rubber tubes and clamps in order to retain any am- 

 monia which might have been given off during the period of 

 incubation. After a period of incubation of seven days the 

 ammonia was drawn directly through another small wash bottle 

 by means of a Richards pump. The small wash bottle contained 

 10 cc. of doubly distilled water to which was added 6 drops of 

 brom thymol blue made up in the proportions suggested by 

 Clark and Lubs. 1 This doubly distilled water had a hydrogen 

 ion concentration of P H 5.6, at which concentration the indicator 

 was yellowish brown. Due to the hydrogen ion concentration 

 decreasing as the ammonia is drawn through, the color changes 

 from green to blue. The length of time taken to change from 

 P H 5.6 to P H 7.0 would, of course, depend upon the amount of 

 ammonia present, and this was thus taken as a criterion of the 



1 Clark, W. M., and Lubs, H. A. The colorimetric determination of hydrogen ion 



bacteriology. Jour. Bact. 2:1-34, 109-136 



191, 236. 1917. 



