Spieazines 21 



carbon and nitrogen atoms in dipeptides are at 

 such angles to one another as to give them a nat- 

 ural tendency to form six-atom rings; and if 

 dipeptides tend to form six-atom rings, then poly- 

 peptides would tend to form spirals with six- 

 atom convolutions, which may be referred to, 

 briefly, as ^^spirazines." Since the configuration 

 of such structures in three dimensions of space is 

 difficult to visualize, several different views 

 thereof are given in the accompanying diagrams. 



It will be noticed that one of the valencies of the 

 alpha carbon atom in these amino acids is always 

 occupied by hydrogen. Chemically it would be 

 possible to attach more complex groups in this 

 position, but it will be found upon experimenta- 

 tion with atomic models that the presence of more 

 complex groups in this position would render the 

 spiral structure impossible, and it will be ob- 

 served that complex groups never occur in this 

 position in the decomposition products of natural 

 proteins. 



The two ends of such a spiral will be different 

 in that one end will be formed of a negative car- 

 boxyl group whereas the other end will be formed 

 of a positive amino group. When the dissimilar- 

 ity of molecular structure at the two ends is 

 taken into consideration, it seems highly improb- 

 able that the ability to grow by assimilation of 



