68 PROPERTIES OF CERTAIN AMINO-ACIDS. [CH. IV. 



Alanine (a-amino-propionic acid) 



CH 3 .CH(NH 2 ).COOH. 



Valine (a-amino-iso-valeric acid) 



*. 



J>CH.CH(NH 2 ).COOH. 



Leucine (isobutyl-amino-acetic acid) 



ru 3 ^>CH.CH 2 .CH(NH 2 )COOH. 

 \^ri 3 ^ 



Phenyl-alanine C 6 H 5 .CH 2 .CH(NH 2 )COOH. 



Tyrosine (/>-oxy-phenyl-alanine) 



(i) 

 CH 2 .CH(NH 2 )COOH ...... (4) 



Tryptophane (^-indol alanine) 



C 8 H 6 N.CH 2 .CH(NH 2 )COOH. 



Cystine (dicysteine or di-/3-thio-a-amino propionic acid) 



CH 2 S S CH 2 



CH(NH 2 ) CH(NH 2 ) 



COOH COOH 



GROUP II. Acid ampholytes. R - COOH. 



CH(NH 2 ).COOH. 



. Aspartic acid CH 2 .COOH. 



(amino-succinic acid) 



CH(NH 2 ).COOH. 



Glutaminic acid CH 2 .COOH. 



(amino-glutaric acid) 



CH 2 



CH(NH 2 ).COOH. 



