1913 1 Johnson: Pigment Formation in Amphibian Larvae 77 



anhydride and glycyl-ty rosin anhydride, giving rise to yellow 

 substances which do not become black as does tyrosin itself. 

 However, a mixture a glycyl-tyrosin anhydride with glycin gives 

 with tyrosinase a rose color changing to bluish green, with alanin 

 it gives a deep red, and with leucin a deep brown color. 



Abderhalden and Guggenheim (1907) studied the action of 

 tyrosinase from Russula delica on tyrosin and various tyrosin- 

 containing polypeptids. Aspartic and glutaminic acids and other 

 amino acids inhibited the action, especially if they were present 

 in strong solution. Polypeptids containing tyrosin residues were 

 colored by tyrosinase, the color being somewhat modified by the 

 nature of the amino acid combined with the tyrosin in the poly- 

 peptid. They conclude that the character of the pigment result- 

 ing from the action of tyrosinase on tyrosin is dependent upon 

 the combination in which the tyrosin exists. 



TABLE 10 



Cleavage products of certain animal and vegetable proteids; ov-albumin, 

 vitellin, and gliadin taken from Hammarsten (1911), gluten from 

 Plimmer (1908). 



Glycocoll 



Alanine 



Valine 



Leucine 



Serine 



Aspartic Acid 



Glutamic Acid 



Cystin 



Phenylalanine 



Tyrosine 



Proline 



Oxyproline 



Tryptophane 



Histidine 



Arginine 



Lysine 



Ammonia 



Ov-albumin 1 Vitellin 4 



Gliadin 



0.61 

 3.16 

 0.0 

 5.11 



1.0 

 1.7 

 3.4 



0.0 



1 Abderhalden and Pregl (1905). 



2 Levene and Beatty (1907). 

 S K. Morner (1901). 



4 Abderhalden and Hunter (1906). 



5 Osborne and Clapp (1906). 



8 Abderhalden and Samuely (1905), and Abderhalden (1909). 

 7 Abderhalden and Malengreau ; Kossel and Kutscher. 



Gluten, from 



wheat 7 



0.4 



0.3 



4.1 



0.7 

 24.0 



1.0 

 1.9 

 4.0 



1.2 

 4.4 

 2.2 

 2.5 



