TAILIEUCHUNG - Ebook Handbook of vitamins (4th edition): Part 2
(BQ) Part 2 book "Handbook of vitamins" has contents: Pantothenic acid, vitamin B6, biotin, folic acid, vitamin B12, choline, vitamin - Dependent modifications of chromatin - Epigenetic events and genomic stability, dietary reference intakes for vitamins. | Robert B. Rucker/Handbook of Vitamins, Fourth Edition 4022_C009 Final Proof page 290 4:54pm Compositor Name: BMani 290 Handbook of Vitamins, Fourth Edition that pantothenic acid was required for the growth of certain bacteria and yeast [1,17,20,22,23]. Next, Elvehjem and associates [21] and Jukes and associates demonstrated that pantothenic acid was a growth factor for rats and chicks [2,16,35,36]. Early nutritional studies in animals also demonstrated that there was loss of fur color in black and brown rats and an usual dermatitis that occurred in chickens fed pantothenate-deficient diets; thus, at one point pantothenate was known as the antigray or antidermatitis factor [37]. Williams coined the name pantothenic acid from the Greek meaning ‘‘from everywhere’’ to indicate its widespread occurrence in foodstuffs. The eventual characterization and synthesis of pantothenic acid by Williams in 1940 took advantage of observations that the antidermatitis factor present in acid extracts of various food sources, ., pantothenic acid, did not bind to fuller’s earth (a highly adsorbent claylike substance consisting of hydrated aluminum silicates) under acidic conditions [22,23]. Using chromatographic and fractionation procedures, which were typical of the 1930s and 1940s (solvent-dependent chemical partitioning), Williams isolated several grams of pantothenic acid for structural determination from 250 kg of liver as starting material [22,23]. With this information, a number of research groups contributed to the chemical synthesis and commercial preparation of pantothenic acid. Pantothenate and its derivatives are now produced mainly through chemical synthesis and the global market in the past decade was >7 Â 106 kg=year [38]. As emphasized throughout this chapter, pantothenic acid, which is sometimes designated as vitamin B5, is the core of the structure of coenzyme A (CoA), an essential cofactor in pathways important to oxidative respiration, lipid .
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