CHAPTER IV. 



THE PREPARATION AND PROPERTIES OF 

 CERTAIN AMINO-ACIDS. 



Amino-acids are compounds in which a H atom of an 

 alkyl group of an organic acid has been replaced by an 

 amino-group. 



CH 3 CH 2 .NH 2 



COOH COOH 



Acetic acid. Amino-acetic acid (Glycine). 



All the physiological amino-acids have the amino 

 group attached to the same carbon atom as that to which 

 the carboxylic group is attached, i.e. they are a-amino-acids. 



CH 3 CH 3 CH 2 .NH 2 



CH 2 CH.NH 2 CH 2 



COOH COOH COOH 



Propionic acid, a-amino- fi-amino-propionic acid, 



propionic acid 

 (alanine). 



The following are the most important amino-acids that 

 have been obtained from proteins by hydrolysis. 



NH 2 

 GROUP I. Neutral ampholytes R - CH.COOH. 



Glycine (amino-acetic acid) 



CH 2 (NH 2 ).COOH. 



