NITROGEN COMPOUNDS 67 



This is a basic ion which is capable of forming many 

 compounds, with alcohols, phenols, aldehydes or 

 acids. It would take us much too far to enter into 

 all these. It must suffice to indicate a few of 

 ammonia's compounds with acids, and especially 

 such as are of biological or physiological importance. 

 AMIDO-ACIDS are formed by an organic acid 

 radical attaching itself by its alkyl-part to the 

 amido-group. Thus we have 



1. Carbamic acid, CH 3 N0 2 , or amido-formic acid 

 from ammonia and formic acid. 



2. Glycocoll or glycocine, C 2 H 5 N0 2 , or amido- 

 acetic acid from acetic acid. Sarcosine, C 3 H 7 N0 2) is 

 methyl-glycocoll, formed by the introduction of a 

 methyl radical into the amido-group of glycocoll. 



3. Alanine, C 3 H 7 N0 2 , or amido-propionic acid 

 from propionic acid. Cy stein is formed from 

 alanine by the radical SH displacing one H from the 

 carbon. 



4. Leucine, C 6 H 13 N0 2 , or amido-caproic acid from 

 caproic acid. 



5. Aspartic acid, C 4 H 7 N0 4 , or amido-succinic acid 

 from succinic acid. 



6. Glutaminic acid, C 5 H 9 N0 4 , or amido-glutaric 

 acid from glutaric acid. 



7. Tyrosine, C 9 H 11 N0 3 , may be looked upon as 

 a combination of alanine and phenol ; it is hydroxyl- 

 phenyl-amido-propionic acid. 



8. Taurine, C 2 H 7 NS0 3 , is amido-ethane-sulphonic 

 acid. 



The ami do-acids are peculiar compounds, and very 

 important constituents of proteins. It has been 

 suggested that all proteins arise from aspartic alde- 



52 



