1270 



GUANINE. 



acteristic of the xanthine bodies, but like hypoxanthine shews 

 a red coloration on the addition of an alkali after treatment 

 with hydrochloric acid and zinc. 



7. Guanine. C 5 H 5 N 5 0. 



NH — CH 



I II 



NH = C C — NH 



I I 



NH — C =N 



\ 

 / 



CO. 



It was first obtained from Peruvian guano, which still pro- 

 vides the most convenient source for its preparation. 



Guanine is also found in small quantities in the pancreas, 

 liver and muscle extract, and among the products of the action 

 of acids on some nucleins. It may also occur in urine, more 

 especially of pigs, in which case it is also found in many of 

 their tissues; additionally in leukhsemic blood in the retinal 

 tapetum of fishes and in their scales, as also in the integument 

 of amphibia and reptiles and in vegetable tissues. 



Fig. 223. Guanine hydrochloride, 

 C 5 II 5 N 5 'J . HC1 + H 2 0. (After 

 Kuhne.) 



Fig. 224. Guanine nitrate, 

 C 5 IIr,N 5 . HN0 3 + HH 2 0. 

 (After Kuhne.) 



It is a white amorphous powder, insoluble in water, alcohol, 

 ether and ammonia. Its insolubility in the latter distinguishes 

 it from xanthine and hypoxanthine. It unites with acids, 

 alkalis and salts to form crystallizable compounds. Of its 

 compounds with acids the most characteristic are those with 

 hydrochloric and nitric acids. 



The compound with nitrate of silver is extremely insoluble 

 in strong boiling nitric acid. 



Reactions. By treatment with nitric acid and caustic soda 

 (Strecker's test) it yields a coloration closely resembling that 



