i9i 2] CURRENT LITERATURE 



343 



d-acetylphenylamino-acetic acid from this substance injected into the liver 

 of dogs, while Neubauer and Fromherz 12 obtained the /-acetylphenylamino- 

 acetic acid as a result of yeast fermentation of the same racemic compound. 



The intermediate chemical transformations by which d-amino-acids are 

 changed into alcohols with one carbon atom less in fermentation have been 



Neubauer and Fromherz and described in the paper cited 

 above. The content of the paper is largely chemical. The conclusion is 

 reached that the amino-acids are not directly transformed into alcohols by 

 hydrolysis and subsequent splitting off of ammonia and carbon dioxide, as 

 epresented by the general formula 



R • CH • NH 2 -COOH+H 2 = R • CH 2 OH+CO,+NH 3 



but that keto-acids are first formed, and these, by loss of carbon dioxide and 

 reduction, are changed into alcohols, the main steps of the process being 

 represented as follows: 



R-CHNH 2 -COOH+0 = R~CO-COOH+NH 3 



R-CO-COOH->R.CHO+CO, 



R - CHO-f 2H = R - CH 2 OH 



This interpretation is the result of experiments in which it was shown (i) that a 

 keto-acid (phenylglyoxylic acid) was formed by the fermentation of phenyl- 

 ammo-acetic acid, and (2) that a keto-acid (^-oxyphenylpyrotartaric acid) 

 yielded the same alcohol by fermentation as the corresponding amino-acid 

 (tyrosin). 1 * A number of side reactions and secondary products occur in this 

 process. The occurrence of the aldehyde is postulated. According to the 

 authors the decomposition of amino-acids by yeasts is hereby shown to follow 

 the same course as the decomposition of these acids in the animal body, except 

 that the postulated aldehyde which is reduced to alcohol by the yeast cell is 

 oxidized to the corresponding fatty acid which is further utilized in metabolism 

 by the animal cell. 



The discovery by Ehrlich 14 of the production of fumaric acid from sugar 

 through the agency of Rhizopus nigricans is of great biological interest, not only 

 because it is the first instance of the occurrence of fumaric acid as a product of 

 metabolism of micro-organisms, but also because of its possible bearing on the 

 origin of unsaturated acids in higher plants. The acid was isolated by Ehrlich 

 from culture solutions, containing much sugar, upon which Rhizopus nigricans 

 was grown. The quantity of acid varies with the sugar content, but in old 

 cultures from which the sugar has disappeared the acid is again consumed. 



"Neubauer, O., und Fromherz, K., Ueber den Abbau der Aminosauren bei 

 der Hefegarung. Zeitschr. Physiol. Chem. 70:326-350. 191 1. 



13 Ehrlich, Felix, Ueber die Vergarung des Tyrosins zu />-Oxyphenyl-athyl- 

 alkohol (Tyrosol). Ber. Deutsch. Chem. Gesells. 44: i39~h6. 1911. 



14 -, Ueber die Bildung von Fumarsaure durch Schimmelpilze. Ber. Deutsch. 



Chem. Gesells. 44:3737-3742. i Q n. 



