

ARGININE. 161 



sufficient bromine water and warming, a reddish coloration ensues 

 which turns deep wine-red, later becoming cloudy, due to the forma- 

 tion of dark amorphous particles (F. KNOOP 1 ). It gives a very beautiful 

 diazo-reaction with diazobenzenesulphonic acid, in solutions made alkaline 

 with sodium carbonate, which according to PAULY is deep cherry-red 

 in dilutions of 1:20000 and still markedly red in 1:100000 (tyrosine 

 gives a similar reaction). 



Several salts of histidine are known; H. PAULY 2 has especially 

 studied the iodized derivatives of histidine and imidazole. 



On feeding cW-histidine to rabbits ABDERHALDEN and WEIL 3 obtained 

 from the urine d-histidine which was crystalline, was as sweet as sugar 

 and showed a specific rotation (a) D = -f-40.15 at 20 C. 



Histidine is sometimes classified in a group, with the two diamino- 

 acids, arginine and lysine which KOSSEL has called the hexone bases, 



d-Arginine ( 5-guanido-a-aminovaleric acid), 



(CH 2 ) 2 , 



CH(NH 2 ) 



COOH 



first discovered by SCHULZE and STEIGER in etiolated lupin- and pumpkin- 

 sprouts, has later been found in other germinating plants, in tubers and 

 roots. GULEWITSCH has found arginine in the ox-spleen, and TOTANI 

 and KATSUYAMA have found it in ox-testicles. It was first found 

 by HEDIN as a cleavage product of horn substance, gelatin, and several 

 proteins, and then by KOSSEL and his pupils as a general cleavage prod- 

 uct of protein substances as a class. The greatest quantity was obtained 

 from the protamines; but the histones and certain plant proteins, 

 edestin and the protein from pine seeds and especially excelsin (14.14 

 per cent), also yield abundant arginine. Arginine also occurs among 

 the products of tryptic digestion (KOSSEL and KuTSCHER 4 ). 



On boiling with baryta-water, as well as by the action of an enzyme, 

 arginase, discovered bv KOSSEL and DAKIN, S arginine yields urea and 

 ornithine. 



1 Hofmeister's Beitrage, 11. 



2 Ber. d. d. chem. Gesellsch., 43. 



3 Zeitschr. f. physiol. Chem., 77. 



4 Schulze and Steiger, Zeitschr. f. physiol. Chem., 11; Schulze and Castoro, ibid., 41; 

 Gulewitsch, ibid., 30; Totani and Katsuyama, ibid., 64; Hedin, ibid., 20 and 21; Kossel 

 and Kutscher, ibid., 22, 25, 26. 



5 Zeitschr. f. physiol. Chem., 41, and Dakin, Journ. of biol. Chem., 3. 



