150 PHYSIOLOGY OF PURIN METABOLISM 



A great deal of careful work has been devoted to the 

 study of the distribution of these ferments in various animal 

 species, in experiments with tissue pulp. 2 Schittenhelm 3 

 was doubtless correct in questioning whether all the differ- 

 ential detail involved should be accepted literally; and 

 whether, if one of these ferments were missed in a given or- 

 gan it would be justifiable to infer therefrom that it is also 

 absent from the living organ. In some aspects, however, 

 investigations of this sort may be productive of results. 



Guanin Gout in the Hog. For example, it was found that 

 in tissues of the hog "guanase" occurs only in small amount 

 and that addition of guanin to extracts of spleen and liver 

 was followed by but insignificant increase in the quantity of 

 xanthin produced in course of the digestion ; but that adenin 

 is freely converted into hypoxanthin. An interesting cor- 

 relation may be recognized in the fact that normally in the 

 urine of hogs the purin bases are more prominent than uric 

 acid, and that there is a disease, guanin-gout of the hog, in 

 which uric acid apparently disappears completely from the 

 urine, and at the same time (in analogy to the deposit of uric 

 acid in the tissues in human gout) guanin is deposited in the 

 muscles, cartilages, and in the liver. The lack of * i guanase ' ' 

 apparently interferes here with the normal formation of 

 uric acid, which in the hog is for the most part further cata- 

 bolized into allantoin. 4 



Nucleases and Deamidases. The chemical conversion of 

 the purin bases must, however, be preceded by their cleavage 

 from the molecule of nucleinic acid, which takes place in the 

 nucleins of the food in the intestine through the agency of 



2 Cf. especially the numerous studies of A. Schittenhelm, as, too, of W. Jones 

 (with C. L. Partridge, W. C. Winternitz, C. R. Austrian, Amberg and others). 



8 A. Schittenhelm, Handb. d. Biochem., 4', 509, 1910; W. Jones, Zeitschr. f. 

 physiol. Chem., 45, 84, 1905. 



3 A. Schittenhelm, Handb. d. Biochem., 4', 509, 1910; W. Jones, Zeitschr. f. 

 W. Jones and C. R. Austrian (Johns Hopkins Univ.), ibid., 48, 110, 1906; L. B. 

 Mendel and J. F. Lyman (Yale Univ.), Jour, of Biol. Chem., 8, 115, 1910; A. 

 Schittenhelm, Zeitschr. f. physiol. Chem., 66, 53, 1910; L. B. Mendel, and P. H. 

 Mitchell (Yale Univ.), Amer. Jour, of Physiol., 22, 97, 1907. 



