PROTEINS 8 1 



Aspartic Acid, C 4 H 7 N04. Aspartic acid is amino-succinic acid and 

 has the following structural formula: 



NH 2 



H GCOOH 

 H GCOOH. 



H 



The amide of aspartic acid, asparagine, is very widely distributed 

 in the vegetable kingdom. Asparagine has the following formula: 



NH 2 



I 

 H GCOOH 



H GCO(NH 2 ). 

 H 



The crystalline form of aspartic acid is exhibited in Fig. 30. 



Aspartic acid has been found among the decomposition products of 

 all the proteins examined, except the protamines. It has not been ob- 

 tained, however, in very large proportion from any of them. The 

 aspartic acid obtained from protein is levo-rotatory. 



Glutamic Acid, CsHgNO^ This acid is a-amino-normal-gliUaric 

 acid and as such bears the following graphic formula: 



NH 2 



H GCOOH 

 H C H 

 H GCOOH. 



H 



Glutamic acid is yielded by all the proteins thus far examined, 

 except the protamines, and by most of these in larger amount than 

 any other of their decomposition products. It is yielded in especially 

 large proportion by most of the proteins of seeds, 43.66 per cent having 

 been obtained by Osborne and Guest 1 by the hydrolysis of gliadin, the 

 prolamin of wheat. This is the largest amount of any single decompo- 

 sition product yet obtained from any protein except the protamines. 



1 Osborne and Guest: Jour. Biol. Chem., 9, 425, 

 6 



