ION EXCHANGE 



403 



matographicall}^ with citrate buffers. Table 9-4 summarizes some of the 

 separations that have been attained within these groups of elements. 

 Samuelson (2) may be consulted for a discussion of other useful inorganic 

 separations. 



The application of ion-exchange methods to nucleic acid chemistry may 

 serve to illustrate separations of particular biochemical importance. 

 Nucleoproteins are apparently an essential constituent of all cells. The 

 composition and nomenclature for yeast nucleoprotein are illustrated 

 below, although it must be pointed out that the more recent experi- 

 mental observations cannot be explained on the basis of a simple tetra- 

 nucleotide structure (27). Thymus nucleic acid, which has also been well 



YEAST NUCLEOPROTEIN 



1 



Adenylic Acid 



i 



Adenine 

 Ribose 

 Phosphoric Acid 



Protein 

 Yeast Nucleic Acid 



YEAST NUCLEIC ACID 



(4 Monoribonucleotides) 



1 



Adenylic Acid 

 Guanylic Acid 

 Cytidylic Acid 

 Uridylic Acid 



MONORIBONUCLEOTIDES 



i 

 Guanylic Acid 



Guanine 

 Ribose 

 Phosphoric Acid 



i 

 Cytidylic Acid 



I 



Cytosine 

 Ribose 

 Phosphoric Acid 



i 

 Uridylic Acid 



1 



MONORIBONUCLEOSIDES 



Adenosine 



i 



Adenine 

 Ribose 



Guanosine 



i 



Guanine 

 Riboso 



Purine Bases 



Adenine 



Guanine 



i 

 Cytidine 



i 



Cytosine 

 Ribose 



Pyrimidine Bases 



i 



Cytosine 



i 



Uracil 



