THE METABOLISM IN GOUT 419 



The Formation of Uric Acid from Nucleic Acid 



This is accomplished by means of a series of ferments. In the stomach 

 by the action of the gastric juice nucleoproteins are changed into protein 

 and nuclein, and from the latter a small amount of nucleic acid is formed, 

 but it is not decomposed in the stomach (Abderhalden and Schittenhelm 

 (c), 1906). Gastric juice and pancreatic juice do not cause any change in 

 the physical and chemical properties of nucleic acid, according to Levene 

 and Medigreceanu. Human duodenal juice obtained by means of a duo- 

 denal tube so changed yeast nucleic acid that it becomes easily soluble in 

 water and dialyzable (Thannhauser and Bommes). Thannhauser and 

 Dorfmiiller(rf) as a result of a careful study concluded that in the duo- 

 denum one mononucleotid is split off the tetranucleotid leaving a new sub- 

 stance, a trinucleotid. Levene (/) has shown that this supposed chemical 

 compound is really a mixture of three mononucleotids. 



The point of great physiological importance shown by Thannhauser 

 is the conversion of nucleic acid without deep splitting of the molecule 

 into substances that are easily absorbed from the upper part of the in- 

 testine. Levene and Medigreceanu (&) had previously shown that intestinal 

 juice forms mononucleotids from yeast tetranucleotid, and the two purin 

 nucleotids are converted into the two nucleosids, adenosin and guanosin. 

 The two pyrimidin nucleotids are not further decomposed. Extracts of 

 intestinal mucosa form mononucleotids and then convert the pyrimidin 

 as well as the purin mononucleotids into the corresponding nucleosids. 

 The purin nucleosids are broken down into d-ribose and purin bases. 

 The pyrimidin nucleosids are not further changed. In fact they are ap- 

 parently not decomposed by any tissue extract (Levene and La Forge). 

 Plasmata of kidney, heart, muscle and liver have the same effect in de- 

 composing nucleic acid as intestinal mucosa. Pancreas plasma, blood 

 serum, and hemolyzed blood convert tetranucleotid into mononucleotids, 

 but here the process stops. 



The ferment that converts tetranucleotid into its constituent mono- 

 nucleotids is called "nuclease." The four mononucleotids are broken 

 down into mononucleosids by specific ferments called "nucleotidases." 

 The conversion of nucleosids into their component base and carbohydrate 

 is brought, about by a third type of ferment called "nucleosidase." 



Jones(c) (1920) found an active agent in the pig's pancreas not de- 

 stroyed by heating which decomposes yeast nucleic acid into its mono- 

 nucleotids. It is not present in the other organs. 



Probably nucleic acid is not broken down in the intestine into the 

 purin bases, but that the mononucelotids or nucleosids are absorbed as 

 such and take a part in the intermediary metabolism (Thannhauser and 

 Czoniczer). Bacteria in the intestine reduce nucleosids to ammonia, thus 



