64 



CHEMISTRY OF THE PEOTEIDS 



CHAP. 



The Stereo-Chemistry of Amino-Acids 



The first investigations into the stereo-chemistry of the 3-carbon 

 compounds have been made by Neuberg and Silbermann, 1 who have 

 endeavoured to throw light on the inter-relationship of amino-acids 

 and glucose. The following 3-carbon compounds are of especial interest, 

 as the first four are primary dissociation products of albumins, while 

 lactic acid is also probably a derivative of alanin : 



1. Alanin 



2. Serin 



3. Stone-cystein 



CH 3 

 CHNH 2 



COOH 

 CH 2 OH 



CHNH 2 



COOH 

 CH 2 NH 2 



CHSH 



COOH 

 4. Protein-cy stein CH 2 SH 



CHNH 2 

 COOH 



lactic acid CH 3 



CHOH 



COOH 



diamino - propionic CH 2 NH 2 

 acid 



OBLNH, 



COOH 

 CH 2 NH 2 



CHOH 



isoserm 



glyceric acid 



COOH 

 CH 2 OH 



CHOH 

 COOH 



The configurative inter-relationship of the laevo-rotatory aldehyde- 

 glyceric acid to the Igevo-rotatory glyceric and tartaric acids Neuberg 

 and Silbermann give as follows : 



