THE BIO-CHEMISTRY OF ANIMALS AND PLANTS 691 



Monoa)nino-N 



Glycine (amino-acetic acid, Braconnot 1820). 

 Alanine (amino-propionic acid, Weyl 1888). 

 Valine (amino-valerianic acid, Gorup-Besanez 1856). 

 Leucine (amino-caproic acid, Proust 181 8). 

 Iso-leucine (amino-caproic acid, Ehrlich 1903). 



Serine (oxy-amino-propionic acid, Cramer 1865). 

 Phenylalanine (phenyl-amino-propionic acid, Schulze and 



Barbieri 1881). 

 Tyrosine (oxy-phenyl-amino-propionic acid, Liebig 1846). 

 Tryptophane (indole-amino-propionic acid, Hopkins and Cole 



1901). 



Aspartic acid (amino-succinic acid, Plisson 1827). 

 Glutarainic acid (amino-glutaric acid, Ritthausen 1866). 



Proline (pyrrolidine carboxylic acid, Fischer 1901). 

 Oxyproline (oxy-pyrrolidine-carboxylic acid, Fischer 1902). 



Dianiino-N 



Ornithine (diamino-valerianic acid, Jaffe 1877). 



Lysine (diamino-caproic acid, Drechsel 1889). 



Arginine (amino-guanidine-valerianic acid, Schulze and 



Steiger 1886). 

 Histidine (amino-imidazole-propionic acid, Kossel 1896). 

 Diamino-trioxy-dodecanic acid (Fischer and Abderhalden 



1904). 

 Cystine (diamino-dithio-d-lactic acid, Wollaston 18 10). 



The proportions in which the various amino acids are obtained 

 from different proteins vary considerably. The quantitative 

 examination of various proteins, by the help of the methods 

 introduced by A. Kossel and E. Fischer, is being carried out at 

 present in many laboratories, and has already furnished most 

 valuable results, e.g. albumins are distinguished from globulins 

 by their complete lack of the glycine group, v^^hilst on the 

 other hand gelatin furnishes as much as 17 per cent, of 

 this substance. The latter protein, however, does not yield 



