246 CHEMISTRY OF THE PROTEIDS CHAP, vii 



The latter by hydrolysis will give rise to HO . OC CO . OH or oxalic 

 acid. Succinic acid arises, according to Seemann, probably from 

 arginin or from a radical which, when albumin is hydrolysed, gives rise 

 to asparagin or aspartic acid. Glutaric acid was not found by Seemann 

 although Zickgraf had previously found it amongst the oxidation 

 products of lysin, and he accounts for its absence by assuming that it 

 is either still in the ' protamin-nucleus,' or that the complex which on 

 hydrolysis gives rise to lysin becomes broken up at once during oxidation 

 in such a manner as to be no longer recognisable. Tyrosin, from the ease 

 with which it splits up, is placed also into the periphery of the albumin 

 molecule. Oxaluramide or oxalan and oxaluric acid, which were first 

 recognised as such by Seemann, the latter derives from arginin, and 

 states that their presence accounts for the deficit in the amount of 

 guanidin which should be there theoretically, judged by the arginin- 

 content of the gelatine molecule. As direct oxidation of arginin does 

 not yield oxaluric acid, but guanidin-butyric acid or guanidin + 

 succinic acid (Kutscher), or urea and ornithin, when treated with 

 barium hydrate (Schulze) or arginase (Kossel and Dakin), Seemann 

 reasons that the arginin group must be attached at its guanidin-end 

 to other amino-acids, from which the oxalic acid compound of the 

 oxaluric acid arises, and he expresses his views in the following figures 

 I. to VI. : 



NH 2 NH 2 E . CH CO N H 



| (H 2 eliminated)^ 



NH 2 CNH 



NH 



CH 2 



CH 2 



ornithin. | 



CH 2 



CHNH 2 



COOH 



arginase . . 



Argimn + another a-ammo-acid 



barium hydrate. radical. 



IL HI. 



