ALBUMINS OR PROTEINS 153 



state. They permitted bacteria to act on tryptophane, and obtained indole, 

 skatole, skatole-carboxylic acid, and skatole-acetic acid. The bacillus of 

 anthrax, and Bacterium coli, in a strong anaerobic solution, produce skatole- 

 acetic acid, while putrefactive bacteria, on the other hand, give skatole- 

 carboxylic acid in conjunction with indole and skatole. The constitution 

 of tryptophane has been recently established by the synthesis of Ellinger 

 and Flamand. 1 It is mdole-a-aminopropionic acid. 



H 

 C 



/ ^ 

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



H!! 



\ // \ / 



C N 

 H H 



Tryptophane 



The common form is dextrorotary both in alkaline and acid solutions. 



It may be mentioned that tryptophane is related to a peculiar metabolic 

 product of the dog, namely, kynurenic acid, which is a y-hy droxy- /?- 

 quinolin-carboxylic acid of the following constitution: 2 



H 



/ \ 



C C.COOH 



/ ^ // 

 HC C 



II I OH 



:c G] 



HC CH 



\ // 



C 



H 



Kynurenic acid 



The transformation of tryptophane into this acid is not yet understood. 

 Possibly some idea of the process may be obtained from the fact that a 

 compound rich in oxygen which can be converted into quinolin is found 

 together with tryptophane. At present, however, we do not know 

 whether this oxy-tn/ptophane corresponds to a primary decomposition 

 product from protein, or whether it is formed secondarily from trypto- 

 phane. 



To the group of heterocyclic building material of protein histidine also 



1 A. Ellinger and C. Flamand, Ber. 40, 3029 (1907). 



2 E. Abderhalden and M. Kempe; Z. physiol. Chem. 52, 207 (1907). 



