88 ADAPTATION AND DISEASE 



happen that free radicles, C, suspended in the cytoplasm may- 

 possess the necessary linkage, and in that case these will act as 

 catalysts or enzymes, first attracting away the radicle a' from 

 A', and then in turn by superior attraction being impelled to give 

 it up to satisfy the linkage " b " of B'. 1 



Possibilities arising out of above View of Enzyme Action 



But if this conception and visualization of enzyme action 

 approaches the fact, do you see where it leads us ? I am not 

 going to take up all the lines of thought and possibilities opened 

 up by this conception, but only those bearing directly on my 

 theme. 



1. In the first place the remains of A left free in the cyto- 

 plasm, if of amphoteric type, may in itself act as a catalyst. 



2. In the second we are given an understanding of the 

 mechanism whereby foreign\ proteins may be utilized by the 

 cell. Those proteins are complexes with multiple linkages : 

 they are composed of combinations of the various amino-acids, 

 and the number of amino-acids is limited. It is, therefore, 

 inevitable that existing enzymes, whether extracellular or intra- 

 cellular, will loosen and detach certain of the radicles, thus dis- 

 sociating the protein and affording food-stufis capable of being 

 utilized by the cell. But doing this, to take the simplest case, 

 the relative numbers of molecules of the different amino-acids 

 presented to the cell — and to its nuclear biophores — will differ 

 from the normal, and, if the exhibition of the foreign protein 



1 This conception of attraction and separation of radicles from a compound 

 is, I admit, difficult to accept when — as we are apt to do — in the mind's eye we 

 picture the molecules of the different salts, e.g. simple salts, like NaCl or KN0 3 , 

 as solid, well defined substances. It must, however, be remembered that in the 

 cell we deal with substances in solution, that the more dilute this solution, the 

 greater the liability towards ionization, towards a loosening of the constituents 

 of a compound one from the other. Under the conditions, therefore, in which 

 enzyme action proceeds, we may safely predicate that a relatively slight attract- 

 ive force is needed to detach molecules or radicles from one compound, causing 

 them to become associated (also loosely) with other molecules, and to be in 

 turn detached from this relatively loose combination. In solution, that is, we 

 have a state of unstable equilibrium, and without entering into a discussion of 

 the relative strength of electric charges of the molecules, or discussing whether 

 we deal with adsorption phenomena or true chemical combination, we can, I 

 think, compromise by agreeing that the conditions in which enzyme action 

 proceeds are those which favour the occurrence of loose molecular combina- 

 tions. 



