HISTOLOGY AND CIIEMISTKY OF FUNGI 59 



(b) Protein-splitting enzymes (proteases): 



Pepsin, which hydrolyzes proteins to albumoses and peptones. 

 Trypsin, which hydrolyzes proteins to peptides and amino- 

 acids in A maniia muscaria and Boletus edulis. 



(c) Urea-splitting enzymes (ureases): 



Urease obtained from Micrococcus urcce, which hydrolyzes urea 

 into ammonia and carbon dioxide. 



(d) Nuclease, which spHts nucleic acid. 



(e) Fat-splitting enzymes (esterases and lipases): 



Lipase in Penicillium glaucum and Aspergillus niger, also 

 Empusa. Phycomyces, which break up fatty oils. 



(/) Glucoside-splitting enzymes: 



Emulsin, which hydrolyzes amygdalin to glucose, hydrocyanic 

 acid and benzaldehyde. Also such other glucosides as saUcin, 

 populin, coniferin which fungi are able to utilize. 



2. FERMENTING ENZYMES. 



(a) Alcoholic fermentation of glucose, levulose, mannose, etc., by 



zymase in yeasts. 

 {b) Lactic acid fermentation of lactose by lactic acid bacteria, 

 (c) Butyric fermentation of lactose by the butyric acid bacteria. 



3. Clotting Enzymes (Coagulation, CurdUng). 



Rennin (Chymosin), which curdles milk. Bacillus mesentericus 

 vulgatus. 



4. OXIDIZING ENZYMES. 



(a) Oxidases, which oxidize alcohols to acids, e.g., the action of 



Mycoderma aceti, etc. 

 {b) Tyrosinase. Russula nigricans and species of Boletus, Lacta- 



rius, etc. 

 (c) Peroxidases, which set free oxygen from hydrogen peroxide, 



causing this substance to blue guaiacum resin. 

 {d) Catalase, which decomposes hydrogen peroxide with the 



evolution of molecular oxygen. 



In concluding this brief study of the enzymes it may be stated that 

 they can be detected by chemic, bacteriologic, serologic and histologic 



