x AUTODIGESTION OF NUCLEAR PROTEIDS 437 



by autodigesting liver. Spleen and liver agree in having the same 

 ferments, but the spleen contains much more oxidase. 



The changes which purin-bases undergo are expressed diagram- 

 matically by Jones and Winternitz in this manner : 



/OH 6 



C 6 H 2 N/ Guanin Adenin C 5 H 3 N 4 .NH 9 6 



NH 2 



-^ ri 2 o o 



03 M 



/OH 6 ^v 



C 5 H 2 N/ Xanthin Hypoxanthin C 5 H 3 N 4 . OH 6 . 



X OH 2 oxydase 



Schittenhelm and Bendix 1 have found that in rabbits the intra- 

 venous injection of guanin increases the uric acid output. 



The allantoin in the body is another product of the oxidative 

 destruction of purin-bases, and in particular of uric acid (Salkowski, 

 'Minkowski, Cohn.). Eppinger 2 has synthetised allantoin from 

 glycolyl-di-urea, which latter becomes oxidized and converted into a 

 ring-compound, both in the test-tube and when administered to dogs in 

 the food. 



NH CH 2 .NH.CONH 2 /NH CHNH CONH 2 



| 

 NH CO. 



/i\n 2 ^n 2 . IN xi . UUIN n 2 

 OCX + O becomes OC 



+ O becomes OC 

 'NH CO X 



'X "TV-/ UG^UlllGQ WV^V + XioO 



The purin-bodies of the urine are not all derived from decomposing 

 nucleo-proteids according to Burian. 3 He believes them to be formed 

 mostly synthetically, for violent muscular exercise during hunger leads 

 firstly to the production of purin-bases and only secondarily to that of 

 uric acid. Hypoxanthin and kreatinin are supposed to be synthetised 

 by one and the same fundamental process during muscular work. The 

 author from his histological researches knows that all cell-activity is 

 accompanied during the stages of restitution by an increase in the 

 size of the nuclear chromatin- segments, and an over-production of 

 purin-bases during violent muscular exercise can be readily accounted 

 for in this way, particularly as during starvation the nucleic-acid 

 radicals will be poorly supplied by the necessary albumin-complements. 



Burian 4 has described a xanthin-oxydase as occurring in extracts 

 of ox-livers which in the presence of a stream of oxygen oxidizes the 



1 A. Schittenhelm and E. Bendix, Zeitschr. /. physiol. Chem. 43. 365 (1905). 



2 H. Eppinger, Hofmeister's Beitrage, 6. 287 (1905). 



3 R. Burian, Zeitschr. /. physiol. Chem. 43. 532 (1904). 



4 R. Burian, ibid. 43. 497 (1904). 



