Derived from the Greek word pántothen, meaning from all quarters, pantothenic acid (C9H17NO5), generally referred to as vitamin B5, is an important factor in metabolic processes, particularly in the Krebs cycle. Historically, it has also been known as chick antidermatitis factor, Bios IIa, and the antigray-hair factor.
First discovered at the turn of the twentieth century and described as Bios, pantothenic acid was known to be essential for yeast growth. R.J. Williams and coworkers isolated crystalline Bios from yeast and named it pantothenic acid in 1933. A few years later, in 1938, Williams isolated the same substance from liver. By 1939, pantothenic acid was determined to be chemically identical to the antidermatitis factor found in chicks. Beta-alanine played an important role in pantothenic acid production, and in 1940, a method to synthesize and crystallize pantothenic acid was established. In 1950, acety l coenzyme A, a derivative of pantothenic acid which reacts with enters at the start of the Krebs cycle and reacts with oxaloacetic acid to form citric acid, was discovered. Its structure and relationship to pantothenic acid was explained the following year.
Vitamin B5 can be naturally derived from a variety of plant and animal sources. Yeasts, animal glands and organs, ground peanuts, herring and cod, royal jelly from bees, and wheat bran and germ are typically rich in pantothenic acid. Moderate amounts are present in avocados, lima beans, broccoli, carrot, cauliflower, cheese, clam, lentils, mushroom, oats, rice, and soybeans. Small amounts can be found in fruits (such as apples, bananas, grapes, lemons, oranges, pineapples, plums, peaches, and pears); vegetables (including kidney beans, cabbage, lettuce, onions, peppers, potatoes, tomatoes, turnips, and watercress); and in some seafood (such as shrimp and lobster.) Pantothenic acid can also be produced synthetically via a chemical reaction involving the condensation of d-pantolactone with salt of p-alanine. To increase stability and make it more useable in a wide variety of products, B5 is often sold in other forms including calcium pantothenate, dexpanthenol, and panthenol (which is also known as pantothenyl alcohol or provitamin B5). Precursors in the biosynthesis of pantothenic acid include a-ketoiso-valeric acid (pantoic acid), uracil (p-alanine), and aspartic acid. Intermediates in the synthesis include ketopantoic acid, pantoic acid, and P-alanine.
Research has shown that pantothenic acid has several interesting properties. It promotes amino acid uptake; in combination with zinc, it can prevent hair from turning gray in rats; it can promote resistance to stress of cold immersion; it may be tied to tumor inhibition; it is necessary in the hatching process of eggs; it is useful in treating vertigo, postoperative shock, certain types of poisoning, and in accelerating wound healing; it is also useful in treating Addison's disease, liver cirrhosis, and diabetes; it is key to the metabolism of carbohydrates, fats, and proteins; and it is also involved in making fatty acids, cholesterol, steroid hormones, and nerve regulators. Perhaps its most important role is in cellular metabolism as a constituent of coenzyme A, which is a factor in the Krebs cycle.
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