Urea-Splitting Ferments. 



13 



those produced by tyramin. But tyramin is more constant in its 

 action and it rarely causes the muscular tremor and apprehension 

 that so frequently follows a large epinephrin injection. 



115 (1293) 



Absence of urea-splitting ferments in the animal tissues. 



By Ahmed E. Shevky (by invitation). 



[From the Laboratory of the Medical Division of Stanford University 

 Medical School, San Francisco.] 



In 1912 Lob and Gutmann 1 published some data from which 

 they concluded that a ferment capable of splitting NH3 from urea 

 existed in the pig's ovaries. Taniguchi 2 in a similar investigation 

 which appeared last year confirmed this with somewhat more 

 detailed data on determinations done with extracts from cow's 

 ovaries. Both investigators used the Kruger and Reich method 

 of ammonia estimation and their technique of extraction involved 

 several hours of incubation. 



In the present study corpora lutea were separated from fresh 

 cow's ovaries, ground with twice its volume of 0.9 per cent. NaCl 

 solution and filtered after standing one hour at room temperature. 

 A similar extract was made from the rest of the ovaries. To I c.c. 

 samples of a 2 per cent, urea solution were added 5, 10 and 15 c.c. 

 of the filtrate and the mixture incubated for one hour at 37 0 C. 

 Samples of urea solution and of the filtrate alone were similarly 

 treated. 



Ammonia estimations on all the samples were done by the 

 aeration-titration method, using Barnett's recently described 

 technique. 3 No more ammonia was found after incubation in the 

 samples of extract and urea mixture than the combined ammonia 

 content of the urea and of the extract samples. 



In the following table figures for the corpora lutea extract 

 are given, extracts from the rest of the ovaries gave similar results. 



1 Lob, W., and Gutmann, S., Biochem. Z., 1912, XLI, 445. 



2 Taniguchi, Y., Acta scholea med. univ. imp., Kioto, 1916, I, 3, 299. 



3 Barnett, G. D., J. Bio. Chem., 1917, XXIX, 459. 



