162 THE PKOTEIN SUBSTANCES. 



Arginine has been prepared synthetically from ornithine (a-5-diamino- 

 valeric acid) and cyanamide by SCHULZE and WINTERSTEIN. Recently 

 SORENSEN and HOYRUP l have prepared d-Z-arginine from ornithuric 

 acid. The a-monobenzoyl ornithine obtained by splitting ornithuric 



N 



acid with barium hydrate yields a-benzoylamino-5-guanido-valeric 

 5 



acid with cyanamide and this on boiling with hydrochloric acid gave 

 5-guanido-a-aminovaleric acid (d-Z-arginine). 



Arginine crystallizes in rosette-like tufts, plates, or thin prisms, is readily 

 soluble in water with alkaline reaction and almost insoluble in alcohol. 

 With several acids and metallic salts it forms crystalline salts and double 

 salts respectively. Its acidified watery solution is precipitated by phos- 

 photungstic acid. The most important salts are the copper-nitrate 

 (C 6 Hi4N4O2)2.Cu(N03)2+3H 2 and the silver salts 



CeHuN^HNOa+AgNOa 



(the more readily soluble) and CeHuN-iC^.AgNOs+fEbO (the more 

 difficultly soluble), and its compound with picrolonic acid (STEUDEL 2 ). 



Arginine is dextrorotatory. For arginine-chloride in watery solu- 

 tion with excess of hydrochloric acid, GuLEwrrscn 3 found (a) D = +21.25 

 at 20 C. The arginine obtained by KUTSCHER in the tryptic digestion 

 of fibrin was racemic arginine. As found by KOSSEL and WEISS (see 

 page 112) arginine or more properly the ornithine is very easily 

 racemerized within the protein molecule by the action of alkali. The 

 racemic arginine can, as RIESSER 4 has shown, during cleavage by means 

 of arginase, yield /-arginine, which is an asymmetric change. In^putre- 

 faction arginine yields ornithine, guanidine, putrescine and 5-amino- 

 valeric acid. 



yNH 2 

 Agmatine (guanidobutylamine), CsHi4N4=HN.C<f 



\NH.CH 2 (CH 2 ) 2 .CH 2 NH 2 , 



is a base obtained by KOSSEL in the hydrolysis of herring sperm, and later by 

 KUTSCHER and ENGELAND 5 from ergot. KOSSEL has also obtained it synthetically 

 from cyanamide and tetramethylendiamine, and in this manner proved its con- 

 stitution. It is produced from arginine by splitting off C0 2 and bears the ^same 

 relation to arginine that putrescine does to ornithine and cadeverine does to 

 lysine (see below). Agmatine gives several crystalline salts as described by 

 KOSSEL. It is precipitated by phosphotungstic acid. 



1 Schulze and Winterstein, Ber. d. d. chem. Gesellsch., 32 and Zeitschr. f. physiol- 

 Chem., 34; Sorensen and Hoyrup, Ber. d. d. chem. Gesellsch, 43 and Zeitschr. f. physiol- 

 Chem., 76. 



2 Zeitschr. f. physiol. Chem., 37 and 44. 



3 Ibid., 27. 



4 Kutscher, Zeitschr. f. physiol. Chem., 28 and 32; Riesser, ibid., 49. 



6 Kossel, ibid., 66 and 68; Engeland and Kutscher, Ceritralbl. f. Physiol., 24, 479. 



