354 DIGESTION 



CHIEF DECOMPOSITION PRODUCTS OF PROTEINS. 



MONOAMINO-ACIDS AND THEIR COMPOUNDS. 



/Glycin or glycocoll (aminoacetic acid), CN 2 (HN 2 )COOH. 

 Alanin (aminopropionic acid), CH 3 CH(NH 2 )COOH. 

 Serin or oxyalanin (oxyaminopropionic acid), 



CH 2 OH.CH(NH 2 ).COOH. 



Valin or aminovalerianic acid, pJ;f>CHCH(NH 2 )COOH. 



Leucin (a-aminoisobutylacetic acid) ^NcHCH 8 CH(NH 8 )COOH. 



Norleucin (a-arnino-caproic acid), 



CH 3 .CH 2 .CH 2 .CH 2 .CH(NH 2 ).COOH. 



Isoleucin (a-amino-/3-methyl-/3-ethyl-propionic acid), 



CH 



C 2 H 5 



CH.CH(NH 2 ).COOH. 



Cystein (a - amino-/5 - thiopropionic acid), CH 2 (SH).CH(NH 2 )COOH, 



which is unstable, two molecules of it easily yielding cystin 

 ropionic acid), 

 COOH.CH(NH 2 ).CH 2 .S.S.CH 2 .CH(NH 2 ).COOH. 



di-(a-amino-/3-thiopropionic acid) , 

 X>OH 



TAspartic or aminosuccinic acid, CH(NH 2 ).COOH. 

 J|J CH 2 COOH. 



Q rt Glutamic or glutaminic acid, CHo/^^aVf OOH 

 ' 



g'-H. fTyrosin (para-oxyphenylaminopropionic acid), 



C p H 4 OH .CH 2 .CH (NH a ) .COOH . 

 ^ P.| ( Phenylalanin (phenylaminopropionic acid), C 6 H 5 CH 2 CH(NH 2 )COOH. 



*-*-d 



Prolin (pyrrolidin carboxylic acid). 

 Oxyprolin (oxypyrrolidin carboxylic acid). 

 Tryptophane (a-amino-/3-indol-propionic acid), 



VN C CH 2 .CH(NH 2 ).COOH. 

 Histidin (/3-imidazol-a-aminopropionic acid), C 6 H 9 N 3 O 2 . 



DIAMINO-ACIDS AND THEIR COMPOUNDS. 



fLysin (a-amino--amino-caproic acid, CH 2 NH 2 (CH 2 ) 3 CH(NH 2 )COOH. 

 A % & 



,NHCH a (CH 2 ) a CH (NH 2 )COOH . 



H o3 rt I 



Ammonia (representing the so-called ' amide-nitrogen,' and liberated 

 from the products of acid hydrolysis of proteins by heating the 

 mixture after addition of alkali). It has not been shown that 

 ammonia is itself one of the ' Bansteine ' of the proteins. 



