COPPER, ENZYMES, AND FERTILIZATION. 99 



the ultimate mechanism of oligodynamic activity. For the pres- 

 ent, however, our concern must be with facts a trifle more imme- 

 diate. From these, it seems to me, we can derive a second sug- 

 gestion. 



The catalytic power of colloidal platinum is destroyed by traces 

 of hydrocyanic acid and can be restored by simple aeration. 

 Moore ('2i 7 ) compares this experience of Bredig and his pupils 

 with the effects of hydrocyanic acid on the peroxidases of the 

 enzymic oxidation system. "If these peroxidases are responsible 

 in tissue cells for the uptake of oxygen by the protoplasm, it may 

 well be that the poisonous action of hydrocyanic acid in such min- 

 ute doses is due to interference with the action of the peroxidases " 

 (loc. cit., p. 231). 



Disregarding the specific case which Moore had in mind, there 

 is implicit here a definite relationship between enzymes and oligo- 

 dynamic action. This relation, however, is also implicit in the 

 copper inhibitions of Lillie. Again the union of saccharase with 

 silver or copper implied by von Euler and Svanberg, together 

 with the natural occurrence of copper in preparations of lipolysin, 

 pancreatic enzymes, and pepsin, now reported, I believe, for the 

 first time, are just what one might expect if the oligodynamic 

 properties of heavy metals are traceable to the activation or inacti- 

 vation of enzymes. These effects must depend on the capacity of 

 enzymes to bind the metal. Until stoichiometrical determinations 

 have. been made nothing further can be said about such unions. 

 But no matter what their nature may be, their occurrence should 

 result in the presence of heavy metals in enzyme preparations when- 

 ever such presence is a physical possibility. 



But the presence of copper raises an apparent difficulty. One 

 might arrive at the paradox that enzymes, by the very nature of 

 the case, must be normally incapacitated. This absurdity is easily 

 dispelled. There is no reason for considering the normal enzyme 

 as saturated with copper. For that matter, the enzyme proper 

 may not be involved at all, for the observed effects can all be 

 explained equally well if the copper is held by organic co-enzymes 

 where these are present. But in this case also we are not com- 

 pelled to consider the co-enzymes as saturated. 



