THE NITROGEN COMPOUNDS 



Animal Proteins 



65 



In view of later discussions it is well to note in this 

 connection certain marked differences in the kind and pro- 

 portions of the cleavage products (building-stones) of the 

 individual proteins. 



For example, glutamic acid is found in the plant 

 proteins in much larger proportion than in animal pro- 

 teins; lysine is absent from the alcohol-soluble proteins 

 hordein, gliadin, and zein, and proline is found in much 

 larger proportion in these than in any others. It is safe to 

 conclude that certain plant proteins cannot be rebuilt 

 into an equal quantity of animal proteins. 



It should be noted, however, that a comparison of 

 vegetable and animal proteins shows in general a close 

 resemblance in the kind of building-stones out of which 



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