ENZYMES 



261 



Courtesy of Drs. R. M. Heiriolt and J. H. Northrop aud Tlie Journal oj (Jeneral 



PJnjsiologij. 



Fig. 10-1. Pepsin. 





Keproduced by courtesy of Drs. M. Kunitz and J. H. Northrop and The Journal 



of General Physiology. 



Fig. 10-2. Trypsinogen. 



C^ I 



Alai35 Valgg Leui23 Ileu84 (Cys-) 13 Metn Sergg Thrye Argsi Hisgs Lysgi 

 Pro69 Phe26 Tyr4i Tryie Aspio- Gkuoo. Glutamic acid is low and valine 

 is high as compared with most proteins, but otherwise there is nothing 

 distinctive about the amino acid content. 



Some enzymes are simple proteins, e.g., pepsin, and others are con- 

 jugated proteins, e.g., lactic dehydrogenase. The latter has a nicotin- 

 amide-containing compound as its prosthetic group. When the enzyme 



