CHAPTER 13 



The Physical Properties of Nucleic Acids 

 D. O. JORDAN 



Page 

 I. Pyrimidines, Purines, Nucleosides, and Nucleotides 447 



1. Structure Determination by X-ray Diffraction 447 



a. Pyrimidines 447 



b. Purines 451 



c. Nucleosides 452 



2. Dissociation Constants 455 



a. Pyrimidines and Purines 455 



b. Nucleosides and Nucleotides 458 



II. Nucleic Acids 461 



1. Structure Determinations by X-ray Diffraction 461 



2. Determination of JVIolecular Weight 470 



a. Deoxypentose Nucleic Acids 470 



b. Pentose Nucleic Acids 474 



3. Acid-Base Properties 475 



a. Deoxypentose Nucleic Acids 475 



b. Pentose Nucleic Acids 480 



4. The Solution Properties of Sodium Deoxypentose Nucleate 483 



a. The Influence of Ionic Strength in Neutral Solution 483 



b. Conclusions as to the Size and Shape of the Deoxypentose Nucleate Ion 



in Neutral Solution 488 



c. The Influence of Changes of pH on the Size and Shape of the Deoxy- 

 pentose Nucleate Ion in Solution 490 



I. Pyrimidines, Purines, Nucleosides, and Nucleotides 

 1. Structure Determinations by X-Ray Diffraction 

 a. Pyrimidines 



The full details of the structures of uracil (I), thymine (5-methyluracil, 

 II), cytosine (III), and 5-methylcytosine (IV), the pyrimidines known to 

 occur in nucleic acids [cf. Bendich, Chapter 3], have not been established 

 by X-ray diffraction. Some conclusions may be drawn concerning their 

 structures, however, from those of some related pyrimidine derivatives 



447 



