GUANYLIC AND INOSINIC ACIDS. 179 



LEVENE and MANDEL l in the liver. As positive cleavage products it 

 yields guanine, pentose (7-xylose according to NEUBERG) and phosphoric 

 acid. According to LEVENE and JACOBS 2 guanylic acid consists of a 

 combination of phosphoric acid and the nucleoside, guanosin, CioH 13 N 2 O5, 

 which is a glucoside-like combination of guanine and pentose (d-ribose). 

 As to the occurrence of glycerin among the cleavage products noth- 

 ing positive is known, and in fact certain investigations disprove the 

 occurrence of this substance. 3 The acid first described by BANG, the 

 /?-acid, is formed from another acid, the a-guanylic acid, with a splitting 

 off of 1 molecule pentose, and the a-guanylic acid contains 1 molecule 

 pentose and 1 molecule guanine for every molecule of phosphoric acid. 

 Correspondingly, as pentose is split off in its formation, the /?-acid is some- 

 what richer in phosphorus and nitrogen than the a-acid, namely, 7.64 per 

 cent P and 18.21 per cent N as compared with 6.65 per cent P and 15.38 

 per cent N in the a-acid. This latter acid differs from the /?-acid in 

 being readily soluble in cold water. 



According to BANG 4 the thymus also contains a simple nucleic acid, 

 namely, an adenylic acid; still this is not based on complete investigations. 



Inosinic Acid, CioH 13 N 4 PO 8 was first isolated by LIEBIG from the 

 flesh of certain animals and then closely studied by HAiSER. 5 It is obtained 

 from beef extracts, and according to the investigations of NEUBERG and 

 BRAHN, FR. BAUER, and LEVENE and JACOBS it is a simple nucleic acid. 6 

 On hydrolysis it yields phosphoric acid, hypoxanthine and pentose, 

 according to the equation: 



CioH! 3 N 4 P0 8 + 2H 2 = H 3 P0 4 + C 5 H 4 N 4 O + C 5 H 10 5 . 



The pentose is according to NEUBERG and BRAHN Z-xylose, but LEVENE 

 and JACOBS 7 have conclusively shown that the pentose is not Z-xylose, 

 but that it is d-ribose. 



Inosinic acid is amorphous, and its solution, containing hydrochloric 

 acid is levogyrate: ( a ) D = 18.5. It gives crystalline salts, among 



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 Ber. d. d. chem. Gesellsch., 42, 2469. 



3 v. Fiirth and Jerusalem, Hofmeister's Beitrage, 10 and 11; Steudel, Zeitschr. f. 

 physiol. Chem., 53. See also Bang, Hofmeister's Beitrage, 11. 



4 Hofmeister's Beitrage, 5. 



5 Liebig, Annal. d. chem. u. Pharm., 62; Haiser, Monatsh. f. chem., 16. 



6 Neuberg and Brahn, Biochem. Zeitschr., 5 and Ber. d. d. chem. Gesellsch., 41, 

 p. 3376; Bauer, Hofmeister's Beitrage, 10; Levene and Jacobs, Ber. d. d. chem. 

 Gesellsch., 41, p. 2703. 



7 Levene and Jacobs, Ber. d. d. chem. Gesellsch., 42. 



