168 J. BADDILEY 



PO3H2 



— o4— — 



OH OH 

 I I I 

 POH MeO-CH-CH-CH-CH-CHj 



-0- 



73x12 



(stable to lOr) 



OH 

 I I 

 ^CH-CH-CH-CH-CHj-OH PO3H 



/ 



31.1.2 



N^^N 



'S> 



-0- 



OH O OH 



NH, ^ HO-CH-CH-CH-CH-CHj 



Adenylic acid b Ribose-3-phosphate 



\ 



PO3H2 



OH O OH 

 I ! I 

 H0-CH2'CH-CH-CH-CHj-0H 



Ribitol-3-phosphate 



g. Guanylic Acids a and b 



A substance known as guanylic acid was first isolated in 1898.^^^ Although 

 at first there was much controversy concerning its occurrence and composi- 

 tion, its existence was fully established eventually by Steudel.^^^ It can be 

 isolated in crystaUine form by hydrolysis of ribonucleic acid,^^' "^ and it 

 was believed that guanylic acid from different sources was a single sub- 

 stance.^^^ On treatment with phosphatase^" or by alkaline hydrolysis"^-'^^ 

 guanylic acid is converted into guanosine, and with nitrous acid it is de- 

 aminated to xanthylic acid.^"- 1^2, iss j^ follows that the phosphate group is 

 situated on the sugar residue of guanosine. The ribose phosphate formed on 

 hydrolysis of xanthylic acid^^^' ^^^ -^y^s alleged to be identical with that 

 obtained from yeast adenylic acid, consequently guanylic acid was thought 

 to be guanosine-3 '-phosphate. However, it is now known that the guanylic 

 acid obtained by hydrolysis of ribonucleic acid is a mixture of a and h 

 isomers, ^^''' ^^^ and it is assumed, by analogy with the adenylic acids, that 



"6 I. Bang, Z. phijsiol. Chern. 26, 133 (1898). 



"» H. Steudel, Z. physiol. Chern. 53, 539 (1907). 



1" P. A. Levene, J. Biol. Chern. 40, 171 (1919). 



"« P. A. Levene and E. Jorpes, J. Biol. Chern. 81, 575 (1929). 



"9 P. A. Levene and W. A. Jacobs, Ber. 42, 2469 (1909). 



180 P. A. Levene and W. A. Jacobs, Ber. 42, 2474 (1909). 



181 P. A. Levene and W. A. Jacobs, Biochem. Z. 28, 127 (1910). 



»82 p. A. Levene and A. Dmochowski, /. Biol. Chern. 93, 563 (1931). 

 1" M. Knopf, Z. physiol. Chern. 92, 159 (1914). 

 18^ W. E. Cohn, J. Am. Chern. Soc. 72, 1471 (1950). 



