VELOCITY OF KEACTION 201 



The explanation of the " Schiitz law " is that it holds for a certain 

 range only, and in this range is an empirical law which gives an 

 approximation to the truth. 



The conclusion may therefore be drawn that in the case of each 

 enzyme, there is in dilute solutions a range of concentration throughout 

 which the activity increases approximately directly as the concentra- 

 tion, and as the concentration increases a further period in which 

 there is also an increase but at a less rapid rate than the concentration, 

 and that finally a maximum effect is obtained beyond which increasing 

 the concentration has no action in increasing the activity. 



