Chapter 10 

 NIACIN 



I. Nomenclature and Formulas 452 



II. Chemistry 452 



A. Isolation 452 



1. Isolation of Nicotinic Acid 454 



2. Isolation of Nicotinamide 454 



3. Separation of Nicotinic Acid and Nicotinamide 456 



4. Isolation of N^-Methylnicotinamide 456 



5. Isolation of 6-Pyridone of N'-Methylnicotinamide 457 



6. Isolation of Other Nicotinic Acid Metabolites 457 



7. Isolation of Coenzj^mes I and II 458 



B. Chemical and Phj'sical Properties 460 



1. Nicotinic Acid 460 



2. Nicotinamide 466 



3. Other Compounds Related to Nicotinic Acid 473 



C. Constitution of Nicotinic Acid 473 



D. Synthesis 474 



1. Nicotinic Acid 474 



2. Nicotinamide 476 



3. Synthesis of Related Compounds of Biological Importance . . . 477 



E. Specificity 478 



III. Industrial Preparation 478 



IV. Biochemical Sj'^stems 480 



A. Introduction 480 



B. Coenzymes Containing Nicotinic Acid 481 



C. Isolation and Identification 481 



D. Occurrence of DPN and TPN 484 



E. Structure and Properties 484 



1. Diphosphopyridine Nucleotide (DPN) 484 



2. Triphosphopyridine Nucleotide (TPN) 488 



F. Mechanism of Action 490 



1. The Coenzymes 490 



2. The Apoenzymes 491 



3. The Coenzyme-Enzyme Complex (Holoenzyme) 492 



4. Point of Hydrogenation 492 



G. Specificity 493 



1. DPN -TPN Specificity 493 



2. Specificity of the Molecule 493 



3. Nicotinamide Mononucleotide 494 



H. Biochemical Reactions 494 



I. Systems 495 



1. Synthesis of High-Energy Phosphate Bonds 496 



2. DPN and TPN in Glycolysis 498 



3. In P.yruvate Metabolism 498 



449 



