CONTENTS XIU 



Page 

 The Concepts of "Proteinogen" and Enzyme-Precursors Con- 

 sidered in the Light of the Specificities of Antigens and Anti- 

 bodies and Their Digestion Products 106 



a. Consideration of Enzyme-Precursors 107 



b. Derivatives of Chymotrypsin and Their Properties . . . 110 



c. Virus-Host Relationship 113 



d. Structural Specificity of Polypeptides of Low Molecular 

 Weight 114 



e. Does Antigen Function as Coenzyme in the Production of 

 Antibody? 116 



f. Specificity of Cleavage Products Derived from Antibody . 118 

 Anti-Antibodies 122 



a. Presence of Serologically Reactive Basic Amino Groups in 

 Antibody Globulins 123 



b. The Directive Influence of Optically Active Catalysts in 

 Producing Optically Active Substances 125 



c. Experiments Dealing Directly with the Question of Anti- 

 Antibody Formation 131 



d. Non-Identity of the Combining Sites for Antigen and Anti- 

 body in an Antitoxin Molecule 134 



e. Further Experimental Data Concerning the Presence of a 

 Common Group in Different Antibodies from a Species of 

 Animal 135 



f. A Comment on the Use of Antigen- Antibody Complex for 



the Production of Anti- Antibodies 137 



g. Acquisition of New Antigenic Specificity by Antitoxins , 138 

 h. Crystalline Diphtheria Antitoxin Antigenically Distinct 



from Normal Serum Components 139 



PART III 

 ANTIBODY AS A SPECIFIC ENZYME INHIBITOR 



A. Nature of the Analogy between Immune and Enzyme Reactions 144 



1. Serological Specificity of Stereoisomeric Conjugated-Protein 

 Antigens 147 



2. Specificity of Enzymes Which Catalyze Stereoisomeric Sub- 

 strates 151 



3. Comparison of the Stereoisomeric Specificities of Immune and 

 Enzyme Reactions 153 



4. Immune and Enzyme Reactions— A Comparison of Reaction 

 Mechanisms 156 



5. Zinsser's View on the Formation and the Role of Antitoxins 159 



