SPECIFICITY OF DEFENSIVE FERMENTS IOI 



that the key can fit into the guide, and push back the 

 bult. The whole of the rest of the lock may, in this 

 case, have suffered considerable alterations. 



The ferments attack a particular substrate at a 

 particular point, and very probably always combine 

 with the groups against which they are directed. It 

 is only secondarily that disturbance occurs of the 

 equilibrium of the compound. So long as this point 

 of attack remains unchanged the ferments are able to 

 act, but the conditions become very different when 

 the much altered product, with all its groupings, is 

 brought into the circulation. If the decomposition is 

 to be a complete one, then a number of ferments has 

 to act. The new conditions, caused by the denatur- 

 ation, produce their full effect after the introduction 

 into the circulation. When we search for ferments by 

 means of boiled tissues, we expose a variety of proteins 

 to the action of ferments. Only that grouping of 

 atoms, towards which the ferment is directed, has to 

 be considered here. All other groups may be neglected, 

 because it would be scarcely possible to presume that 

 the boiling has produced structural conditions which 

 are accessible to ferments, although the natural sub- 



o 



strate was not so accessible. Rather must we reckon 

 with the possibility that a too extensive denaturation 

 will so strongly modify an original grouping, that is 

 accessible to ferments, that the ferment then becomes 

 inactive. The grouping has now become foreign to it. 



