XX CONTENTS 



VI. The Role of Acetic Acid, Formic Acid, and Propionic Acid in the 

 Intermediary Metabolism of Fats (rontiniietl) 



a. Glycogen Synthesis 268 



(a) The Effect on Total Glycogen 268 



(b) The Effect on the Composition of Glycogen 269 



b. Fatty Acid Synthesis 269 



c. Cholesterol Synthesis 270 



d. Protoporph.vrin Synthesis 270 



e. Uric Acid Synthesis 271 



f. Amino Acid Synthesis 271 



g. Miscellaneous Syntheses Other Than via the Tricarboxylic Acid 



Cycle 271 



(a) Succinic Acid 272 



(b) Acetopyruvic Acid 272 



(c) a-Ketoglutaric Acid 273 



h. The Formation of Citric Acid 274 



i. The Formation of Acids Related to Citric Acid 277 



(5) Resume of the Metabolism of Acetic Acid 278 



2. Formic Acid and Formate Metabohsm 279 



(1) Introduction 279 



(2) The Nature of the Active Formyl Group 280 



(3) Reactions in Which Formate Plays a Role 282 



a. Purine Synthesis 282 



b. Thymine Synthesis 284 



c. Serine Synthesis 284 



d. Formate as a Source of the Labile Methyl Group 285 



e. Formate in the Catabolism of Histidine 286 



f . Miscellaneous Compounds Related to Formate 287 



(4) Factors Involved in Formate Utilization 287 



3. The Metabolism of Propionic Acid 288 



VII. The Metabolism of Branched-Chain Acids, Hydroxy and Keto Acids, 

 Dicarboxylic Acids, Tricarboxylic Acids, Fatty Acid Amides, Fatty 



Acid Aldehydes, and Hydrocarbons 291 



1. Branched-Chain Acids 291 



( 1 ) a-Substituted Acids 292 



(2) /3-Methyl-Substituted Acids 294 



(3) /3-Phenyl-Substituted Acids 295 



(4) Miscellaneous Substituted Acids 296 



2. Hydroxy and Keto Acids 301 



(1) or-Hydroxy and a-Keto Acids 301 



a. a-Hj^droxyisobutyric Acid 302 



(2) /3-Hydroxy and /3-Keto Acids 302 



(3) Miscellaneous Hydroxy and Keto Acids 304 



3. Polycarboxylic Acids 305 



(1) Dicarboxylic Acids 305 



