THE NATURE OF ENZYME ACTION 



By W. M. BAYLISS, M.A., D.Sc, F.R.S. 

 Assistant Professor of Physiology in University College, London 



PAGE 



Catalysis 281 



Reversibility 284 



Velocity of Reaction 289 



Effect of Concentration of Enzyme. 



Effect of Temperature. 



Accelerators and Retarders. 



Co-enzymes 297 



Zymogens 298 



Chemical and Physical Properties of Enzymes . . .298 



Mode of Action . 299 



Complex Systems 303 



Conclusion 305 



Literature 305 



Catalysis 



All investigators who have had occasion to consider the nature 

 of the chemical changes taking place in living organisms must 

 have been struck with the comparative ease with which highly 

 stable bodies are split up under these conditions. Sugar is 

 oxidised to carbon dioxide and water, egg-white is hydrolysed 

 to amino-acids and other simple bodies. Under ordinary 

 laboratory conditions, strong acids and high temperature or 

 similar powerful agents are necessary to effect such changes. 

 Schonbein may be mentioned as one of those who early called 

 attention to this circumstance. 



Now although, at first sight, the powers referred to may 

 be regarded as a distinguishing characteristic of systems which 

 are called " living," it must be remembered that there is a large 

 and increasing class of phenomena, known to chemists as 

 " catalytic," which manifest properties in many ways analogous. 

 Ox}^gen and hydrogen, for instance, combine at ordinary tem- 

 peratures so slowly that the production of water is not to be 

 detected, and the application of the high temperature of a flame 

 or electric spark is needed. But the presence of a minute 



281 



