102 CHEMISTRY OF THE PROTEIDS CHAP. 



and caproic acids; further, S-amino-valerianic acid, x which may be 

 derived either from ornithin, by a splitting off of the a-amino-group 

 (H. Salkowski), or by an opening up of the pyrrol -ring of the 

 tt-pyrrolidin - carboxylic acid ; succinic acid (Blumenthal) ; phenyl- 

 propionic acid or cinnamic acid ; j?-oxyphenyl- propionic acid or 

 hydro-para-cumaric acid ; and indol-propionic acid. 



The changes produced in chemically pure tryptophane or indol- 

 amino-propionic acid by putrefaction have been carefully studied by 

 Hopkins &iid Cole. 1 The first to observe that tryptophane is formed 

 at. an ear. ly period, during the putrefaction of albumins was Claude 

 Bernard; who observed the colour reactions with the halogens. 

 Hopkins and Cole obtained indol and all the related substances 

 skatol, skatol-carboxylic (indol-acetic) acid, and skatol-acetic (indol- 

 propionic) acid by bacterial action, and therefore tryptophane is 

 the precursor of these substances in putrefaction. Under the 

 influence of anaerobic bacteria, tryptophane yields large amounts of 

 indol-propionic acid, owing to the removal of amino-groups from the 

 amino-acids : 



. CH(NH 2 )COOH 

 CH 



H 



Try tophane or indol-amino-propionic acid + Hydrogen = 



2 COOH + NH 3 

 /CH 



] N 



H 



Indol-propionic acid + Ammonia. 



Baumann 2 found analogous changes in tyrosin, when it was 

 digested with putrefying pancreas, and Nencki, 3 when tyrosin was 

 subjected to the anaerobic growth of the Rauschbrand bacillus. 



HO . C 6 H 4 . CH 2 . CH(NH 2 )COOH + H 2 



Tyrosin or oxyplienylamino propionic acid + Hydrogen = 



HO . C 6 H 4 . CH 2 . CH 2 . COOH + NH 3 



Oxyphenyl- propionic acid + Ammonia. 



1 Hopkins and Cole, Journal of Physiology, 29. 451 (1903). 



2 Baumann, Ber. d. deutsch. chem. Ges. 1451 (1879). 



3 Nencki, ibid. 7- 1593 (1874). 



