412 JOSEPH H. PRATT 



The Purin Bodies 



The relation of uric acid to a large group of compounds has been defi- 

 nitely established (E. Fisher(&)). They are all derivatives of purin (a 

 word coined from purum uricum). The purin substances of the animal 

 body with the exception of uric acid were formerly called nuclein bases 

 (Kossel), alloxuric bases (Kossel and Kriiger) or xanthin bases. The en- 

 tire group including uric acid was embraced under the name of alloxuric 

 bodies (Kossel and Kriiger). 



Purin may be considered as made up of two characteristic parts. 



N C 



(1) A pyrimidin nucleus C C and 



N C 



C N\ 



(2) An imidazol nucleus ^0 



C X / 



A condensation of these two rings gives the framework of purin. 



N C 16 



To these constituent 



C C - !N\ atoms numbers have 2 5 7v 



C been assigned (Fischer) 



In this structure of the purin bases an acid is united to urea. This is 

 called a ureid. If as in the case of purin there are two molecules of urea 

 it is termed a diureid. From uric acid and the other purins two ureids can 

 be obtained. One of these, parabanic acid, is a compound of oxalic acid 

 and urea. 



COOH H 2 N CO NH 



| + )CO | >CO + 2 H 2 O 



COOH HoN- 7 CO NH 



oxalic acid urea parabanic acid 



The other ureid is alloxan, a compound of mesoxalic acid and urea. 

 NH 2 COOH NH CO 



CO +' CO CO' CO +2 H 2 O 



NH 2 COOH NH CO 



urea mesoxalic acid alloxan 



