Senin, 06 September 2010

Functions and Benefits of Vitamin B12



Vitamin B12 is the largest and most complex of all vitamins. Vitamin B12 is the generic name for a specific group of cobalt-containing corrinoids from biological activity in humans. What is interesting is the only known metabolite contains cobalt, which gives a water-soluble vitamin its red color. This group of corrinoids is also known as cobalamin. The principal cobalamins in humans and animals are hydroxocobalamin, adenosylcobalamin and methylcobalamin, the latter two are active coenzyme forms. Cyanocobalamin is a form of vitamin B12, which is widely used clinically because of the availability and stability. Converted into active agents in the body.
 
In 1934, three researchers won the Nobel Prize for Medicine for discovering the exceptional properties of vitamin B12. It was found that the consumption of large quantities of raw liver, which contains large quantities of vitamin B12, can save the lives of patients with pernicious anemia previously incurable. This discovery allows you to save 10,000 people a year in the United States alone. Vitamin B12 was isolated from liver extract in 1948 and its structure was explained by seven years later.

Function
Vitamin B12 is essential for the formation of blood cells, nerves, and covers the various proteins. It is therefore essential to prevent certain forms of anemia and neurological disorders. He is also involved in the metabolism of fats and carbohydrates and is essential for growth. In humans, the functions of vitamin B12 mainly as a coenzyme in intermediary metabolism. Two metabolic processes depend on the Vitamin B12:
 
  1. The methionine synthase reaction with methylcobalamin
  2. Methylmalonyl CoA mutase reaction of adenosylcobalamin
In methylcobalamin form of vitamin B12 is a cofactor for methionine synthase directly, the enzyme that converts homocysteine back to methionine. There is evidence that vitamin B12 is essential for the synthesis of folate polyglutamates (active coenzymes necessary for development of neural tissue) and the regeneration of folic acid during the formation of red blood cells.
 
Methylmalonyl CoA mutase converts 1-methylmalonyl CoA to succinyl-CoA (reaction important in the metabolism of fats and carbohydrates). Adenosylcobalamin is also a coenzyme in the ribonucleotide reduction (which provides blocks for the synthesis of DNA).
 
Food Sources
Vitamin B12 is produced exclusively by microbial synthesis in the gastrointestinal tract of animals. Therefore, the protein products of animal origin are a source of vitamin B12 in food, especially meat organs (liver, kidneys). Other good sources are fish, eggs and dairy products. Food, hydroxo-, methyl-and 5'-deoxyadenosyl Cbl-Cbl are the mainstream. Plant foods do not contain vitamin B12, except those from microbial contamination. The bacteria in the intestine synthesize vitamin B12, but not in normal conditions in the regions where absorption occurs.
 

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