GUANIN. 377 



prepared from di-chlor adenin, resembles guanin very much and 

 inasmuch as it may be looked upon as an oxidation product of 

 adenin Fischer is inclined to believe that it may be found in the 

 animal body. From guanin it is distinguished by the fact that the 

 sulphate contains one molecule of water which is not driven off at 

 120°, and also by not yielding guanidin on cleavage. 



More recently Traube ^ has effected the synthesis of guanin by 

 starting out with guanidin and cyanacetic acid ethyl ester. A 

 pyrimidin body was obtained which with formic acid gave the purin 

 base guanin. 



Guanin has been met with in a very large number of tissues, both 

 animal and vegetable ; in the liver, pancreas, lungs, retina, in the 

 thymus gland of the calf, and in the testicle substance of the bull ; 

 in the scales of the bleak, and in the swimming bladder of fish, as 

 well as in the excrements of birds, of insects, as the garden spider, 

 in which it occurs with a small quantity of uric acid (Weinmann), 

 and is to be regarded as a decomposition product of proteids in the 

 tissues of the spider. It is also found in the spawn and testicle of 

 salmon, and Schulze and others have shown it to be present in the 

 young leaves of the plane-tree, of vine, etc., also in grass, clover, 

 oats, as well as in the pollen of various plants. Kresling found 

 it in the pollen of the fir with hypoxanthin and xanthin. Guanin 

 and hypoxanthin, but no xanthin, are present in the seeds of 

 Randia dumetorum (Vogtherr). Schiitzenberger isolated it, together 

 with hypoxanthin, xanthin, and carnin, from yeast which had been 

 allowed to stand in contact with water at or near the body tempera- 

 ture. On the other hand in sterile auto-digestion of yeast and of 

 pancreas Kutscher found only adenin and guanin ; in the former 

 also the hexon bases, ammonia, leucin, tyrosin, asparaginic acid and 

 the base CgH^N^O^. As pointed out on p. 367 in the presence of 

 bacteria, perhaps owing to the formation of nitrous acid, the guanin 

 is changed to xanthin. Levene obtained guanin and adenin from the 

 nucleinic acids prepared from pancreas and from tubercle bacilli. 



Pathologically, it occurs in the muscles, ligaments and joints of 

 swine suffering from the disease known as guanin gout. Normally, 

 guanin, like adenin, is present in muscle tissue only in traces. It 

 has never been found in the urine, though xanthin has been mis- 

 taken for guanin by some. In their extensive studies upon the 

 alloxuric bases Kriiger and Salomon failed to obtain guanin from 

 10,000 liters of urine. Possibly the base was changed to xanthin 

 by the nitrous acid formed in the process, although this is not the 

 case with adenin which was found in the urine. Altogether the 

 presence of guanin in urine remains yet an open question. In some 

 cases of exudates and transudates guanin is present in considerable 

 amounts (Jaksch). 



• Berichte, 33, 1371. 



