NUCLEIC ACIDS 147 



THE PARTIAL DECOMPOSITION PRODUCTS OF THYMUS 

 NUCLEIC ACID 



Levene and Mandel (a) (1908) prepared an indefinite substance from 

 thymus nucleic acid which produced phosphoric acid, levulinic acid and 

 thymine. They conclude that the substance is thymine-hexa-nucleotide. 



Levene and Jacobs (i) (1913) prepared a substance from thymus 

 nucleic acid that forms guanine and levulinic acid. It is possibly guanine- 

 hexa-nucleoside. 



If these two substances, one a nucleoside and the other a nucleotide, 

 indicate that thymus nucleic acid is constructed throughout upon nucleo- 

 sides and nucleotides, then the later work of Levene and Jacobs (j) (1912) 

 suggests the structure of thymus nucleic acid. Their argument is based 

 upon the assumed structures of three compounds which they obtained by 

 the mild hydrolysis of thymus nucleic acid with sulphuric acid. 



1. Hexa-thymidine di-phosphoric acid 



2. Hexa-cytidine di-phosphoric acid 



3. Hexa-cytosine-thymine-di-nucleotide 1 



HO\ 



O=P OH 

 O/ 

 HO\ 



O=P O . C H 9 O 5 . C 5 H C > T ,O 2 

 HO/ 



Thymidine Di-phosphoric Acid 



HO\ 



0=P O . C C H 9 3 . C 5 H C N 2 2 

 HO/ | 



O 

 H0\ | 



O^P O . C 6 H 9 O 3 . C 4 H 4 N 3 O 

 HO/ 



Thymine-Cytosine Di-nueleoti.de 



H0\ 



O=P O . C H 9 O 3 . C 4 H 4 N 3 O 

 HO/ | 



0\ 



O=P OH 

 HO/ 



Cytidine Di-phosphoric Acid 



1 In the nomenclature of the decomposition products of nucleic acids the prefixes 

 "'penta" and "hexa" have reference to the carbohydrate groups. "Hexa" means "from 

 thymus nucleic acid"; "penta" means "from yeast nucleic acid." 



