80 A. I. RIXGER 



7. Xormal Lcucin or a-amino caproic acid. 

 CH 3 



I 

 6-CII 2 



Y-CH 2 



a-CHXH 2 



! 

 coon 



These amino acids are neutral in reaction, but have the property of 

 uniting with both acids and alkali. Glycocoll, for example, can combine * 

 with XaOII forming sodium glycocollate: 



CH 2 XII, CH 2 NIIo 



| + XaOH - > | + H 2 



COOII COONa 



Glycocoll Sodium Sodium Glycocollate 

 hydroxid 



which is still capable of combining with an acid radical, because of the 

 free basic amino radical ( XII 2 ). 



On the other hand, glycocoll can combine with an acid like hydrochloric, 

 forming a well defined salt, glycocoll hydrochloric!, which is acid in re- 

 action. 



CH 2 XII 2 CII 2 XH 3 C1 



| + 1101 - I 



COOH COOII 



Glycocoll Hydrochloric Glycocoll Imlrochlorid 



acid 



and is capable of uniting with alkali because of its free acid radical 

 ( COOII) known as carboxyl. 



B. Dibasic Mono Amino Acids. 



1. Aspartic acid or a-amino succinic acid. 

 COOII 



cc-CHXIL 



I 

 COOH 



