ION-EXCHANGE CHROMATOGRAPHY 



217 



TABLE I 



pK Values of Bases, Ribosides, and Nucleotides" 



'^ From Levene and Bass'^ unless otherwise noted. 

 Ribosides and ribonucleotides except for thymidine and thymidine-5'-phcsphate. For isomeric nuc- 

 leotides, see Table H. 



'' From .-ipectrophotometric observations. '^ 



■^ Alberty et al. (at 25°C.).» 



" Taylor.i' 



/ A. Albert, Biochem. J. 54, 646, 1953. 



" Ogstnn." 



Sugar group. 

 ' 5' Deoxynucleotides: R. O. Hurst, A. M. Marko and G. C. Butler, J. Biol. Chem. 204, 847, 1953. 

 ' Presumably same as riboside. 

 * Cavalieri et alA^ 



' Not measured but presumably similar to base. 

 '" Shugar and Fox." 



II. The Separation of Bases and Nucleosides 



1. Ionic Properties 



All purine and pyrimidine bases have at least one group capable of form- 

 ing an ion. Most have more than one, and can ionize, under proper condi- 

 tions, to form either anions or cations (see Table I). The ribosides have 

 properties very similar to those of the bases, since the very weakly acid 



'^ P. A. Levene and L. W. Bass, "The Nucleic Acids." Chemical Catalog Co., New 



York, 193L 

 '' W. E. Cohn, unpublished observations. 



'^ R. A. Alberty, R. M. Smith, and R. M. Bock, J. Biol. Chem. 193, 425 (1951). 

 '5 H. F. W. Taylor, J. Chem. Soc. 1948, 765. 



'« L. Cavalieri, S. E. Kerr, and A. Angelos, /. .4m. Chem. Soc. 73, 2567 (1951). 

 " A. G. Ogston, J. Chem. Soc. 1935, 1376. 

 '» D. Shugar and J. J. Fox, Biochim. et Biophys. Acta 9, 199 (1952). 



