56 WHAT IS LIFE 



a hundredfold. But no enzyme had ever yet been 

 isolated when it was announced in September, 1926, 

 that James B. Summer, assistant professor of biologi- 

 cal chemistry at Cornell Medical College, had suc- 

 ceeded in the isolation and crystallization of urease. 



Enzymes are produced by the cells of living or- 

 ganisms, and enzyme action belongs to the cardinal 

 functions of living cells. Some recent research de- 

 scribes enzymes as being electrochemical in character 

 (Fodor). The enzymes are organic catalyzers (some 

 enzymes acting hydrolytically), and synthesizers. 



The study of enzyme action is of foremost interest 

 in connection with the proteins and carbohydrates. 

 Recently, too, it has been urged that the process of 

 fermentation and that of respiration show relation- 

 ship.^ H. von Euler maintains that in respiration 

 the endproduct CO2 results not only from splitting- 

 products of carbohydrates, but that often also the 

 fats (open-chain compounds) and constituents of 

 the complex proteins contribute. 



The problems of the dynamics of the living or- 

 ganism are intimately bound up with physico- 

 chemical processes — all chemical reactions and all 

 physicochemical processes involve problems of en- 

 ergy (heat, work, etc.). It is well known that all 



* Hans von Euler, "Enzyme und Co-Enzyme als Ziele und Werkzeuge der 

 chemischen Forschung." Sammlung chemischer und chemisch-technischcr Vor- 

 tr&ge, XXVIII, Heft 6 und 7, 242. 



