PROTEOLYTIC ENZYMES OF SOIL FUNGI 529 



3. Both exo- and endoenzjrmes are produced by microorgan- 

 isms on protein-containing and protein-free media, but the 

 activities of the enzymes from organisms grown on the media 

 containing proteins are greater than those obtained from organ- 

 isms growTi on the protein-free media. 



4. The age of the culture, at which the most active enzymes 

 are obtained, depends on the organism itself, its rapidity of 

 growth, and the nature of the waste products produced in the 

 medium. 



5. Fibrin and crystalline egg-albumen are decomposed by both 

 the exo- and endoenzymes of the organisms used. 



6. Small quantities of ammonia were found to be produced in 

 the decomposition of peptone and casein by the proteolytic en- 

 zymes of the microorganisms studied. This fact indicates the 

 probable presence of desamidases among the enzymes produced. 



The writer wishes to express his most sincere thanks to Prof. 

 T. B. Robertson and to Dr. C. L. A. Schmidt for many helpful 

 suggestions in carrying out this problem, and to Prof. C. B. 

 Lipman for reading the manuscript. 



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