496 



VICTOR C. MYERS 



Nucleic Acid 

 (nuclease) 



I 

 Nucleotids 



(nucleotidase) 



Nucleosids 



I nucleosidase) 



Nucleoprotein 

 (protease) 



Adenin 

 (adenase) 



4 

 Hypoxanthin 



(oxidase) 



Guanin 

 (guanase) 



4 

 Xanthin 



(oxidase) 



Protein 



- Uric Acid 



We are familiar with the chemical structure of the purins owing 

 chiefly to the researches of Emil Fischer and his pupils. An apprecia- 

 tion of the chemical structure of this group of compounds is of material 

 aid in obtaining an adequate understanding of purin metabolism. 



IN 60 N = C(NH 2 ) HN CO 



20 5C N7\ HO C NH (NH 2 )C C NH 

 | | C8 || || \CH || || \CH 



O-IN \tVy " -IN i/ f -i- 1 ~ ~~~ v-/ " -LN // j^\ "~ " \*j "* _IN // 



Purin Nucleus or Adenin Guanin 



Skeleton ( 6-amino-purm) (2-amino-6-oxy purin) 



CO HN CO HN CO 



C 



HO C NH 00 C NH - OC 



|| \CH 



r c N/ 



Hypoxanthin 

 (6-oxypurin) 



|| \CH C( 



HN C N/ HN C NH/ 



Xanthin Uric Acid 



(2, 6-dioxypurin) 2, 6, 8-trioxy-purin 



It has been claimed that in man about half the uric acid is subject to 

 a further enzymatic change (uricolysis). This, however, is still a dis- 

 puted question although in animals the greater part of the uric acid is 

 undoubtedly converted to allantoin. 



