72 THE NITROGENOUS DERIVATIVES OF THE ALBUMINS. 



the protamins, as also of all complex albumins, both of animal and 

 vegetable character, which have been examined in this direction. 

 Among these may be mentioned fibrin, keratin, spongin, collagen, 

 conglutin, elastin, egg-albumin, casein, etc. Kutscher, moreover, 

 obtained these bodies among the final decomposition-products of 

 tryptic digestion, and showed that that portion of Kiihne's anti- 

 peptone which can be precipitated with phosphotungstic acid con- 

 sists to the extent of from 30 to 31 per cent, of these hexon bases. 



The free bases, like the protamins, are Isevorotatory, while their 

 salts, which are formed through union with acids and salts of the 

 heavy metals, are dextrorotatory. These salts can be obtained in 

 crystalline form, and it has thus been possible to determine the 

 formula? of the free bases. 



Arginin. On hydrolytic decomposition arginin yields urea and 

 ornithin. The substance is therefore regarded as a guanidin deriva- 

 tive, similar to kreatin, in which one amido-group has been replaced 

 by the ornithin radicle. The correctness of this supposition has 

 since been established through the synthesis of arginin from cyana- 

 mide and ornithin. Ornithin, moreover, is now known to be #, 

 o-diamido-valerianic acid, and the structural formula of arginin 

 may hence be represented as follows : 



NH 2 NH 2 



NH = C NH.CH 2 .CH 2 .CH 2 .CH.COOH. 



Its relation to guanidin and kreatin, as also its decomposition into 

 urea and ornithin, is further shown : 



X NH 2 /NH, 



CHNH) CHNH) 



\NH, \N(CH 3 ).CH 2 .COOH 



Guanidin. Kreatin. 



CN.NH 2 -f CH(CH,).NH 2 .COOH = C 



Cyanamide. Methyl-glycocoll. \N(CH 3 ).CH 2 .COOH 



Kreatin. 



NH 2 

 CN.NH 2 + CH 2 .CH 2 .CH 2 .CH.COOH = CHNH) 



| | \NH.CH 2 .CH 2 .CH 2 .CH.COOH 



Cyanamide. NH 2 KH 2 



Ornithin. NH 2 



Arginin. 



X NH 2 

 CHNH) 



\NH.CH 2 .CH 2 .CH 2 .CH.(NH 2 ).COOH + H,O 



Arginin. 



/NH 2 



-f CH 2 ( NH 2 ).CH 2 .CH 2 .CH(NH 2 )COOH. 



Ornithin. 



Urea" 



On oxidizing: arginin with barium permanganate Kutscher 

 obtained guanidin, guanidin-butyric acid, and ethylene-succinic acid. 

 He concludes that the process occurs in two phases, as represented 

 by the equations : 



