chapter  8
26 Pages

- Pantothenic Acid

The discovery of pantothenic acid followed the same path that led to the discovery of other watersoluble vitamins evolving from studies utilizing bacteria and single-cell eukaryotic organisms (e.g., yeast) and eventually animal models [1-35]. Although the widespread occurrence of pantothenic acid in food makes a dietary deciency unlikely, the use of experimental animal models [4-13] and antagonistic analogs, such as ω-methyl-pantothenate [23,24], and, in the past several decades, the feeding of semi-synthetic diets free of pantothenic acid [25-34] have helped to dene pantothenate’s physiological functions. Largely the efforts of research groups associated with R. J. Williams, C. A. Elvehjem, and T. H. Jukes led to the identication of pantothenic acid as an essential dietary factor. R. J. Williams demonstrated that pantothenic acid was essential to the growth of certain bacteria and yeast and provided observations essential to the elucidation of pantothenic acid [1,15,18,19,21,22]. Next, Elvehjem et al. [12,13,20] and Jukes et al. demonstrated that pantothenic acid was a growth factor for rats and chicks [2,15,35]. Other observations on the role of pantothenic acid as a nutritional factor important in mammalian embryonic development are described by Kimura et al. [25] and Emerson [34]. Early nutritional studies in animals also demonstrated that there was loss of fur color in black and brown rats

8.1 Introduction and History ...................................................................................................... 325 8.2 Chemical Perspectives and Nomenclature ........................................................................... 326 8.3 Food Sources and Requirements .......................................................................................... 327

8.3.1 Pantothenic Acid Requirements ............................................................................... 327 8.3.2 Food Sources ............................................................................................................ 328

8.4 Intestinal Absorption and Maintenance ............................................................................... 329 8.5 Cellular Regulation of Pantothenic Acid, CoA, and Pantothenic Kinase ............................ 330

8.5.1 Cellular Transport and Maintenance ........................................................................ 330 8.5.2 Pantothenic Acid Kinase .......................................................................................... 331 8.5.3 CoA Formation ......................................................................................................... 332 8.5.4 CoA Regulation and CoA Synthetase ....................................................................... 333 8.5.5 Acyl Carrier Protein ................................................................................................. 333

8.6 Selected Physiological Functions of ACP and CoA ............................................................. 335 8.6.1 CoA and ACP as High-Energy Intermediates .......................................................... 335 8.6.2 Synthetic versus Catabolic Processes Involving Pantetheine ................................... 336 8.6.3 Acetylations as Regulatory Signals .......................................................................... 336 8.6.4 Acylation Reactions .................................................................................................. 337

8.7 Pantothenic Acid Deciency, Clinical Relationships, and Potential Interactions Involving Polymorphisms ..................................................................................................... 337 8.7.1 Polymorphisms or Gene Defects in Enzymes Involved in CoA Synthesis .............. 339

8.8 Pharmacology ....................................................................................................................... 339 8.9 Toxicity .................................................................................................................................340 8.10 Status Determination ............................................................................................................ 341 References ...................................................................................................................................... 341

and an unusual dermatitis that occurred in chickens fed pantothenic acid-decient diets; thus, at one point, pantothenic acid was known as the anti-gray or anti-dermatitis factor [36].