430 SCIENCE PROGRESS 



chloride. In such an instance the electrolyte must be con- 

 sidered as a co-enzyme, just as the H- ion may be with regard 

 to pepsin. The term co-enzyme is in this connection one of 

 degree ; but in its original sense as used by Bertram when 

 describing the importance of manganese in the action of laccase 

 it was more confined. The term adjuvants has therefore been 

 adopted to cover all substances which accelerate enzyme action, 

 whatever their nature. 



There is not much recent work on this subject, and it seems 

 very probable that many of the substances hitherto known as 

 co-enzymes will be found to affect different parts of the 

 complex systems in which enzymes act, and the term will 

 become obsolete. 



Vulquan and Lisbonne (191 2) found that the amylase of 

 malt was inactive without the presence of sodium, potassium or 

 calcium chloride, or of potassium nitrate. Factors on which 

 this may depend have been mentioned under " Electrolytes." 



Similarly early workers, e.g. Loewenhart, referred to bile 

 salts as co-enzymes, but as already stated, the action of the 

 cholates — as shown by Terroine and later by De Jonge (191 7) 

 (see " Dispersion ") — can now more readily be explained 

 physically. 



The loss of activity of urease — shown by Falk in 191 7 — as a 

 result of dialysis can readily be explained physically, but it is 

 not quite clear why the urease can be reactivated on the addition 

 of a very small quantity of fresh urease. 



Neuberg (191 8) refers to keto acids and potassium phosphate 

 as co-enzymes in relation to fermentation by yeast, but in this 

 instance too a physical explanation could be found. 



Some observers have found that certain enzymes help others. 

 For instance, Massai (191 8) found that the action of pancreatic 

 trypsin on casein was supplemented by erepsin from animals 

 or yeast. It is possible that the adjuvant action of these two 

 enzymes plays an important part in the completion of digestive 

 processes. 



Of unique interest is the observation of Lombroso (191 6) 

 with reference to the adjuvants of the glycolytic enzymes of the 

 pancreas. This investigator found that the blood corpuscles 

 were a most important factor in the effectivity of this enzyme. 

 As presumably the effect of the blood corpuscles is purely 

 physical, general support is given to physical explanation of 

 adjuvant phenomena. 



Antagonists. — ^When dealing with the action of electrolytes, 

 reference was made to the inhibiting effect of salts, and to this 

 point many of the general statements made regarding " Adju- 

 vants " apply. Just as it is possible that certain of the 

 properties of the so-called co-enzymes may be explainable 



