88 THE CLEAVAGE-PRODUCTS OF THE ALBUMINS. 



as a diamino-acid. Collectively the three were termed hexon bases 

 by Kossel. It is now known that histidin is not a diamino-acid, 

 however, but for convenience' sake it is considered in this connection. 



Arginin and lysin are common components of the albumins, 

 while diamino-trioxydodecanic acid has only been obtained from 

 casein. But there is evidence to show that it also or closely related 

 bodies may occur in other albumins. 



Arginin is a guanidin derivative of a, d-diamino-valerianic acid 

 (ornithin) and represented by the formula : 



NH, NH, 



NH = C NH CH, CH 2 CH a CH COOH. 



On hydrolysis it is decomposed into urea and ornithin : 



NH, NH, NH 2 



Arginin = C = O -f CH 2 CH, CH, CH COOH 



NH, 



Urea. 



Ornithin. 



The correctness of this formula is supported by the synthesis of 

 arginin from ornithin and cyanamide, viz. : 



NH a NH 2 



CN NH, + CH, CH, CH, CH COOH = Arginin. 

 Cyanamide. Ornithin. 



On oxidizing arginin with barium permanganate, Kutscher 

 obtained guanidin, with guanidin-butyric acid as intermediary 

 product. 



It is very interesting to note that ornithin can give rise to putres- 

 cin, viz., to tetramethylene-diamin, a ptomain which is formed 

 during the putrefaction of albuminous material, and which also has 

 been found in the urine in association with cystin. Thus far this 

 transformation has been effected only through the agency of micro- 

 organisms, but there is no reason to suppose that their presence is 

 essential, and that in the tissues of the living body the same proc- 

 ess cannot also occur. This transformation may be represented by 

 the equation : 



CH 2 (NH 2 ).CH 2 .CH 2 .CH. (NHACOOH = CO, -f CH,(NH 2 ).CH ? .CH 2 .CH 2 .(NH 2 ) 

 Ornithin. Putrescin. 



Lysin. Lysin is apparently a homologue of ornithin, and is 

 represented by the formula CH 2 (NH 2 ).CH 2 .CH 2 .CH 2 .CH(NH 2 ).- 

 COOH; it is thus , e-diamino-capronic acid. On^ hydrolytic 

 decomposition it yields ammonia, oxalic acid, propionic acid, and 

 notably acetic acid. On oxidation of lysin with barium perman- 



