1907.] Studies on Enzyme Action. 365 



In the case of enzymes other than those which affect carbohydrates, the 

 range of activity would appear, however, often to be greater than is 

 ever manifest in the case of enzymes of the sucroclastic class. Thus lipase 

 hydrolyses not only fats but also numerous ethereal salts ; and many of the 

 polypeptides prepared by Emil Fischer are hydrolysed by trypsin, which 

 clearly exercises a wide range of activity. 



As the only radicles common to the ethereal salts and to the polypeptides 

 respectively are in the one case the group — CO.O — and in the other the group 

 >N.C.CO — present in the amino-acids represented generally by the formula 

 NH 2 .CHE.CO.OH, it is to be supposed that these simple groups are the 

 active centres and that the specific influence of the enzyme is exercised at 

 these centres. The variations observed in the activity of an enzyme towards 

 a variety of hydrolytes are, from this point of view, to be ascribed mainly to 

 differences in the stability of the hydrolytes ; a single key, as it were, is 

 provided which fits a variety of locks almost equally well ; but as the locks are 

 constructed with springs varying in stiffness, the effort which must be exerted 

 to open the locks varies from lock to lock. But the interesting problem 

 to be solved in this connection is whether, in the case of compounds 

 such as the proteins, several junctions may not be resolved practically 

 simultaneously by " compound " keys, as it were. 



Bertrand's remarkable observations* on the limiting oxidising power of 

 Bacterium xylinum have shown that configuration is of consequence even in 

 the case of oxydases. It is conceivable that the oxidation of compounds such 

 as the higher fatty acids is a regulated process consequent on the attachment 

 of an oxidase to the terminal carboxyl group, the which oxidase serves to 

 bridge over the interval between this group and some more or less distant 

 CH 2 group and to locate oxygen against it. 



* ' Ann. Chim. Phys.,' 1904, ser. 8, vol. 3, pp. 181—288. 



VOL. LXXIX. — B. 2 E 



