CONTENTS XI 



13. The Physical Properties of Nucleic Acids by D. O. Jordan 447 



I. Pyrimidines, Purines, Nucleosides, and Nucleotides 447 



II. Nucleic Acids 461 



14. Optical Properties of Nucleic Acids and Their Components by G. H. Beaven, 



E. R. Holiday, and E. A. Johnson 493 



I. Introduction 493 



II. Bases, Nucleosides, and Mononucleotides 495 



III. Nucleic Acids and Polynucleotides 514 



IV. Ultraviolet Dichroism 532 



V. Infrared Absorption Spectra 545 



15. Nucleases and Enzymes Attacking Nucleic Acid Components by G. Schmidt 555 



I . Introduction 556 



II. Enzymes Catalyzing the Cleavage of Bonds Between Nucleotides. . . 558 



III. Enzymes Catalyzing the Hydrolytic Cleavage of the Phosphoryl 

 Groups of Mononucleotides 590 



IV. Nucleoside Kinases 594 



V. Enzymes Acting on the Amino Groups of Purine and Pyrimidine Com- 

 pounds 595 



VI. Enzymes Acting on the Linkages Between the Basic and the Carbo- 

 hydrate Groups of Nucleic Acid Derivatives 600 



VII. Xanthine 0.\idase 609 



VIII. Enzymes Involving the Opening of the Purine Ring 614 



IX. Enzymes Involving the Opening of the Pyrimidine Ring 619 



X. Some Data Concerning the Intracellular Distribution of Enzymes of 



Nucleic Acid Metabolism 623 



XI. Addendum 625 



Author Inde.x 627 



Subject Index 655 



