ARGININ. 437 



sel in 1890 that lysatinin (p. 425) on boiling with baryta gave urea 

 led Schulze and Likiernik to make a similar experiment with arginin. 

 They also obtained urea. As already pointed out lysatinin was even- 

 tually shown to be a mixture of arginin and lysin. This was the 

 first time that urea was successfully prepared by the mere hydration 

 of a cleavage product of proteids. It indicated that arginin was 

 without doubt a guanidin derivative. 



Subsequently Schulze and Winterstein ^ demonstrated that the 

 cleavage of arginin by means of baryta or other alkali yielded urea 

 and ornithin, this change being represented by the equation : 



C,HjAO, + H,0 = CO(NH^, + C,Hj^A- 



Abgihik. Oenithik. 



Ornithin had been demonstrated by Jaff6, twenty years before, to 

 be an intermediate waste product in the metabolism in chicken. 

 When benzoic acid is introduced into the body of mammals, as is 

 well known, it unites with glococoU and is eliminated as hippuric 

 acid. In birds it combines with ornithin and is excreted as orni- 

 thuric acid, CjgHj^N^O^ . The latter was shown by JaflPS to be a 

 dibenzoyl ornithin and the base itself he regarded as a diamido 

 valerianic acid although at the time no proof of this could be 

 adduced. On treatment with nitrous acid Schulze and Winterstein 

 demonstrated the presence of two amido groups in ornithin. This 

 fact and the formation of urea led them to ascribe to arginin the 

 following structure which subsequent investigations proved to be 

 correct. 



NH 

 ]i^H.CH,.CH,.CH,.CH(NHj) .COOH. 



It is evident from this structure that arginin is closely related to 

 creatin. 



NH, 

 C.NJ 



INH 

 N(CH3).CH,.C00H. 



Analogous to the synthesis of creatin from cyanamid and sarkosin, 

 it is possible to effect the synthesis of arginin, as Schulze and Win- 

 terstein ^ have done, by the action of cyanamid on ornithin. These 

 investigators supplied additional evidence in favor of the correctness 

 of the structure above given by converting ornithin by dry distilla- 

 tion and hence closing the chain, into a pyrrolidin-like body. 



In 1889 Udr^nszky and Baumann' pointed out the close relation 



> Zeits. phydol. Ohenu, 26, 1, 1898 ; 34, 144. 



'Berichte, 32, 3191 (1899) ; Zeits. physiol. Chem., 34, 128. 



^ZeiJts. physiol Chem., 13, 590. 



