416 JOSEPH H. PRATT 



zation of the amino-purins in the organism the oxypurins, hypoxanthin and 

 xanthin are formed. These by oxidation are converted into uric acid. 

 Finally, in all animals except man and the ape uric acid is further oxidized 

 into allantoin, the real end product of purin metabolism. 



The second group of primary constituents of the nucleic acid molecule 

 are the pyrimidin bases. 



1 N = CH 6 



2 HO CH 5 



II II 



3 N CH 4 



The formula shows that pyrimidin has the structure of an ureid, 

 and that it possesses a part of the purin nucleus. Emil Fischer has pro- 

 duced pyrimidin synthetically from urea and acrylic acid (CH 2 = CH 

 COOH). 



Kossel and his co-workers have found the following derivatives of 

 pyrimidin in nucleic acids. 



HN CO HN = C NH 2 HN CO 



II II II 



OC CH OC CH OC C CH 3 



I II I II II 



HN CH HN CH HN CH 



uracil cytosin thymin 



2.6 dioxypyrimidin 2. oxy 6 aminopy- 5 methyl 2.6 dioxy- 



rimidin pyrimidin 



Animal and Plant Nucleic Acids. There are two distinct types of 

 nucleic acid, one of which is obtainable from the nuclei of animal cells 

 and the other from the nuclei of plant cells. Kossel discovered the final 

 hydrolytic products of nucleic acid by his studies of thymus nucleic acid 

 and yeast nucleic acid. 



Jones (d) gives the following table in his monograph on nucleic acids. 



Hydrolytic Products of Nucleic Acid 



Of Plant Origin Of Animal Origin 



Phosphoric acid Phosphoric acid 



Guanin Guanin 



Adenin Adenin 



Cytosin Cytosin 



Uracil Thymin 



Pentose Levulinic acid 



