CHAPTER XXI 



URIC-ACID METABOLISM AND GOUT ' 



These subjects have been the o])jeet of such a prodigious amount 

 of research that it is far beyond the seope of tliis work to review the 

 histor}' and the details of the investigations. Such a review is also 

 particularly unnecessary, since it can be found in the works on phys- 

 iological chemistry and various treatises on metabolism. Conse- 

 quently the attempt will be made in this chapter merely to give, as 

 brietiy as possible, the views now most generally accepted concerning 

 the nature and metabolism of uric acid, and its relation to patho- 

 logical processes. For the historical discussion, indicating by what 

 devious steps we have reached our present understanding concerning 

 this long-disputed subject, the reader is referred to the articles men- 

 tioned below, upon which I have drawn freely. A particularly clear 

 summary of the subject is given by Walter Jones in his monograph on 

 nucleic acids.^ 



THE CHEMISTRY OF TTRIC ACID 



It is the very great service of Emil Fischer to have shown us the 

 structure of the uric-acid molecule, the empirical formula of which, 

 C3H4N4O3, had long been known. He demonstrated that it is a mem- 

 ber of a group of substances, which are all characterized by being 

 built up about a certain nucleus, C-N^. As the simplest member of 

 the group is a synthetically formed body, purine, the nucleus is called 

 the "purine nucleus." The structural relations of the better-known 

 "purine todies" to this purine nucleus and to each other is clearly 

 shown by their structural formula?, as given below : 



The atoms in the "purine nucleus" are arranged as follows: 



N(i)— C(6) 



I I 



C(2)— C(5)— N(t) 

 N(3)-C(4)-N(9) 



To each atom has been given a inimber, as shown, for the purpose of 

 facilitating reference to the location of various atoms and groups 

 that are attached to this nucleus. The structure of i)uriiu' itself is 

 as shown on the following page : - 



1 CompU'te rpviows arp irivcn l)y 1'. TI. .McCniddcii, "rric At'id," Xcw ^Orlc, lOOn; 

 Wionor, Krpol)nissf dor Plivsiol.," 1002 (1), fj;");") ; ibid., l!t().S (2), :?77; Burian and 

 Sdmr, Pfliifrcr's Arcli., ino'o (SO), 241; 1001 ( S7 ) . 2:5!); Sc'liiltonludni. Ilaiidh. d. 

 Tliocliciii.. 1010, IV (,), 4S0; Bru'-srh and Scliittcnholm, "Die NukleinstolTwoHisel 

 und seine St.r)run<,'('n," .Jena, 1010; Waller -lones, "Niudeie Acids," Monograplis on 

 JJioclieniistrv, 1014. An excellent sinnniai\- of i-eccnt woik is i;iven bv Benedict, 

 Jour. l.ab. Clin. Med., lOlG (2), 1. 



-In these formuhe the symbols of llie atoms foiining tiie purine nucleus are 

 in heavy type. 



618 



