PRODUCTS OF PANCREATIC DIGESTION. 183 



along with phenylalanine seem to be characteristic, especially where casein 

 is used. But these residues are easily decomposed by hydrochloric acid 

 with separation of the constituent amino acids. It is likely that much 

 more complex bodies will be secured by further extension of the processes. 



The hexone bodies as end products of definite composition 

 are of great theoretical importance because of their relation 

 to the protamines referred to in a former chapter. Some of 

 these protamines break down almost quantitatively into argi- 

 nine and the other hexones, so that the latter may well be 

 looked upon as nucleus structures which unite, with loss of 

 water, to form the more complex molecules. These diamino 

 acids seem to bear about the same relation to the peptones and 

 proteins that sugar bears to dextrin and starch. As in the 

 hydrolysis of starch the nature of the end product depends on 

 the nature of the agent of cleavage, so in proteolysis the same 

 thing is true ; acids and enzymes work nearly in the same way, 

 but not absolutely. 



In this connection it should be pointed out that Siegfred has 

 separated by a somewhat peculiar method of treatment a num- 

 ber of bodies which he calls trypsin-fibrin peptones and pepsin- 

 fibrin peptones which may be represented by the following 



formulas : 



trypsin antipeptone a CioHnNsOs 

 trypsin antipeptone /3 CuHisNsOs 

 pepsin peptone a 

 pepsin peptone /3 



The pepsin peptone a seems to be related to the antipeptones 

 in this way : 



G^NeO, + H 2 = C 10 H 17 N 3 5 + CnHx.NsOs 



It is urged by Siegfried that the constant optical rotation of 

 these various products is a satisfactory evidence of their con- 

 stant composition. In connection with these formulas the 

 formulas of the hexone bodies may be recalled: 



histidine, GH 9 N 3 O 2 

 arginine, CoH^N^a 

 lysine, C 6 H 14 N 2 O 2 



