TRYPTOPHANE. 153 



The inactive acid and its compounds show somewhat varying 

 properties. 



Oxyproline (oxy-a-pyrolidine carboxylic acid), C 5 H 9 NO3. This acid, 

 whose constitution is not understood was first obtained by E. FISCHER 1 

 on the hydrolysis of casein and of gelatin. It dissolves readily in water; 

 has a specific rotation of (a) D = 81.04, and the solution has a sweet 

 taste. Oxyproline crystallizes in beautiful colorless plates and gives- 

 a readily soluble copper salt. LEUcns 2 has prepared two isomeric 

 inactive oxyprolines which were crystalline. 



Tryptophane (indolaminopropionic acid), 



C.CH 2 .CH(NH 2 )COOH 

 Ci iH 12 X 2 2 = C 6 



NH 



is one of the cleavage products of the proteins formed in tryptic diges- 

 tion and other deep decompositions of the proteins, such as putrefaction, 

 cleavage with baryta-water or sulphuric acid. It gives a reddish-violet 

 product with chlorine or bromine which is called proteinochrome. NENCKI 3 

 considered tryptophane, which name is generally given to this acid, 

 as the mother-substance of various animal pigments. 



Tryptophane was first prepared in a pure form by HOPKINS and 

 CoLE, 4 and they considered it as skatolaminoacetic acid. After ELLIN- 

 GER showed that skatolcarbonic acid (SALKOWSKI) and skatolacetic 

 acid (NENCKI) were indolacetic acid and indolpropionic acid respectively, 

 and after the synthesis of d--tryptophane by ELLINGER and FLAMAND, 5 

 the nature of this substance as indolaminopropionic acid was established. 



By condensation of ^-indolaldehyde with hippuric acid ELLINGER 

 and FLAMAND prepared the azlactone (lactimide) : 



N 



I I 



co-o 



1 Ber. d. d. chem. Gesellsch., 35 and 36. 



2 Ber. d. d. chem., Gesellsch., 38. See also Leuchs and Felser ibid., 41. 



3 In regard to tryptophane, see Stadelmann, Zeitschr. f. Biologic, 26; Neumeister, 

 ibid., 26; ^encki, Ber. d. d. chem. Gesellsch., 28; Beitler, ibid., 31; Kurajeff, Zeitschr. 

 f. physiol. Chem., 26; Klug, Pfiiiger's Arch., 86. 



4 Journ. of Physiol., 27. 



5 Ellinger, Ber. d. d. Chem. Gesellsch., 37 and 38. With Flamand, ibid., 40, and 

 Zeitschr. f. physiol. Chem., 55. 



