240 



WALDO E. COHN 



phosphates and related substances, utihzing borate complexing, is shown 

 in Fig. 22.^° The separation of ribose-2- and-3-phosphates, which was an 

 essential part of the preparation and characterization of these two sub- 

 stances and of their identification as parts of the adenylic and guanylic 

 acids a and b, respectively, is showTi in Fig. 23.*'' ^^ 



In the course of these separations, it was found that an unexpected 

 isomer of ribose phosphate appeared®^ • *^ whenever ribose-2- or 3-phosphate 



02 



04 06 08 



LITERS THROUGH COLUMN 



10 



I 2 



Fig. 25. Separation of deoxycytidine-5'-phosphate and cytidine-5'-phosphate by 

 anion exchange in a formate system with borate present." 

 Exchanger: same as Figs. 22, 23, and 24, in formate form. 



Solutions: 0.1 M Na formate plus .0005 M tetraborate (peak 1) ; 0.1 M Na formate 

 (peak 2). 

 Sorbed material: ca. 5 mg. each in 10 ml. 0.01 M NH4OH. 



was heated in acid for a period which produced a large degree of hydrolysis 

 to free ribose (which was identified as such by the method of Khym and 

 ZilP^). This new isomer, which was separable in a sulfate (also in a chloride) 

 system without borate*^ from the 2 and 3 isomers and partially separated 

 from the 5, has been identified as the 4 isomer. In Fig. 24^^ are showTi the 

 appearance of ribose-4-phosphate upon acid treatment and its separation 



«» J. X. Khym and W. E. Cohn, /. Am. Chem. Soc. 75, 1153 (1953). 



6' J. X. Khym, D. G. Doherty, E. Volkin, and W. E. Cohn, /. Am. Chem. Soc. 75, 



1262 (1953). 

 « J. X. Khym and W. E. Cohn, J. Am Chem. Soc. 76, 1818 (1954). 

 «3 J. X. Khym, D. G. Doherty, and W. E. Cohn, for J. Am.. Chem. Soc, 77, in 



press. 

 " J. X. Khym and W. E. Cohn, Biochim. el Biophys. Acta 15, 139 (1954). 



