INOSINIC AND GUANYLIC ACIDS. 183 



On hydrolysis it yields phosphoric acid, hypoxanthine and pentose, 

 according to the equation: 



The pentose, whose somewhat disputed nature has been discussed 

 on page 178, is combined with hypoxanthine in a glucoside-like com- 

 bination forming the pentoside inosine, which, according to LEVENE and 

 JACOBS, is combined with the phosphoric acid, like an ester by means 

 of the 6-carbon atom of the pentose (ribose). 



Inosinic acid is amorphous, syrupy, readily soluble in water and pre- 

 cipi table by alcohol. It is lae vo-rotatory ; for the Ba salt containing 

 hydrochloric acid NEUBERG and BRAHN found (a) D = 18.5 at 16 C. 

 It gives several crystalline salts among which the barium salt, which is 

 soluble with difficulty in water, must be mentioned. 



In regard to the preparation of this acid we must refer to the works 

 of HAISER, NEUBERG and BRAHN, LEVENE and JACOBS mentioned in 

 footnote 5, page 182. 



Guanylic acid. This acid, which was first prepared by BANG from 

 the pancreas has also been found by JONES and ROWNTREE in the spleen 

 and by LEVENE and MANDEL 1 in the liver. As cleavage products it yields 

 guanine, pentose and phosphoric acid and therefore its simplest formula 

 is CioHuNsPOg. This formula is accepted also by STEUDEL and BRIGL 

 and by LEVENE and JACOBS, while BANG basing his views on the results 

 of elementary analysis gives the formula C44He6N2oP4O34. Accord- 

 ing to this formula the acid would contain besides, guanine, pentose and 

 phosphoric acid also an unknown residue, C4Hio0 2 , and according to BANG 

 is not a simple nucleic acid but would occupy an intermediary position 

 between the inosinic acid and the thymus nucleic acid. In opposition 

 to this it must be remarked that LEVENE and JACOBS 2 have recently 

 prepared the crystalline brucine salt of the acid and the analysis of this 

 salt as well as the barium salt substantiates the first mentioned, simple 

 formula. In regard to the pentose of guanylic acid see page 178. 



The acid first described by BANG, the /3-acid, is soluble with great diffi- 

 culty in cold water and rather readily soluble in boiling water. It is easily 

 precipitated by acetic acid from the solution of the alkali combination 

 in water. The /3-acid may, according to BANG, be derived from another 

 guanylic acid, the a-guanylic acid, by the action of the alkali. The 



1 Bang, Zeitschr. f. physiol. Chem., 26; with Raaschou, Hofmeister's Beitrage, 4; 

 Jones and Rowntree, Journ. of biol. chem., 4; Levene and Mandel, Biochem. Zeitschr. 

 10. 



2 Steudel and Brigl, Zeitschr. f. physiol. Chem., 68; Bang, ibid., 69 and Bioch. 

 Zeitschr., 26; Levene and Jacobs, Journ. of biol. Chem., 12. 



