THE METABOLISM IN GOUT 415 



as early as 1875. This according to Walter Jones was a lucky guess, 

 while Stanley Benedict regards it as a beautiful example of chemical 

 prophecy. 



With the amino- and oxypurins two tautomeric formulas are possible. 

 The derivatives of the saturated purin are designated imino- and keto 

 (lactam) compounds. Those looked upon as formed from the unsaturated 

 purin are the amino- and enol (lactim) compounds. 



NH CO N = C OH 



I OH\ |* 



CO C NH C C NH 



OH 



NH C -NH N C N 



Lactam form of uric acid Lactim form of uric acid 



Nucleoproteins, Nuclein, and Nucleic Acid. The purin bases are dis- 

 integration products of nucleic acid which is found in the nuclei of all 

 animal and plant cells. This was Kossel's epoch making discovery. Nu- 

 cleic acid is found in cells combined with various proteins. These com- 

 pounds are the nucleoproteins. The proteins bound to nucleic acid are 

 of the type of protamin and histon. They are thus chiefly composed of 

 diamino-acids. The nucleoproteins when digested with pepsin-hydro- 

 chloric acid split off protein. The insoluble residue that remains is called 

 "nuclein." This is probably a salt of protein and nucleic acid. Although 

 resistant to peptic digestion nuclein by hydrolysis with alkalies is decom- 

 posed into protein and nucleic acid. By long continued boiling with 2 

 to 5 per cent sulphuric acid the nucleic acids break down into their primary 

 constituents phosphoric acid, sugar, purin bases and pyrimi'din bases. 

 The disintegration of nucleoproteins is shown in the following diagram: 



Nucleoprotein 



Protein Nuclein 



Protein Nucleic acid 



i 



Phosphoric acid Sugar Purin bases Pyrimidin bases 



The most characteristic constituents of nucleic acid are the purin bases. 

 Protein contains no purin (Kossel). Only the amino-purins, adenin and 

 guanin exist in the nucleic acids of plants and animals. By the deamini- 



