|Vitamin B12 Usage And Synthesis|
|outline||Vitamin B12, which is called VB12 for short, also known as cobalamin, and is one of the B vitamins, is a class of complex organic compounds containing cobalt Corrin class ,and contained trivalent cobalt in similar porphyrin Corrin plane at the center of the ring.It is the largest and most complex vitamin molecule that has been discovered. It is also the only vitamin with metal ion. The crystal is red, it is also called red vitamin.The plant does not contain VB12, and can not produce VB12. The liver is the best source of VB12, then from milk, meat, eggs, fish and so on.VB12 is an essential coenzyme in the synthesis of RNA and DNA. The lack of VB12 in vivo can cause pathological changes in the nervous system such as peripheral nerve and central nervous system.
The discovery of vitamin B12, first of all, should be attributed to the research work carried out by the people in the treatment of pernicious anemia named by British physician Addison.The pernicious anemia at that time is a type of cancer that is incurable. In 1926, Minot and Murphy found it can cure the disease by ingestion of large amounts of raw liver , for which they won the 1934 Nobel Prize in physiology and medicine prize. Following the discovery of Minot and Murphy, people successfully cured the disease by liver concentrate. In 1948, the riches, British Smith and Parker et al, respectively from the liver concentrate isolated a red crystal, named for vitamin B12. In the same year, R. west of Columbia University in the United States confirmed by injections of vitamin B12 to effective treatment of pernicious anemia.Then in 1955, D. Hodgkin,et al. using X-ray analysis to determine the crystal structure of vitamin B12. He also won the 1964 Nobel Prize in chemistry in 1972, Woodward successfully completed the total synthesis of vitamin B12.
Figure 1 is the source of vitamin B12
|Chemical properties||Deep red crystalline or amorphous crystalline powder, odorless and tasteless. Melting point is 210~220 ℃ (carbonized to black). 1g product can be dissolved in 80mL water, soluble in alcohol, insoluble in acetone, ethyl ether or chloroform. Anhydrous is easy to absorb moisture, crystallization of Vitamin B12 in neutral and acidic solution to air and better thermal stability, in alkali, strong acid and reducing agent is not stable, not resistant to light and ultraviolet.|
|Characters||It is the deep red crystal or crystalline powder, odorless, tasteless, hygroscopic strong. Slightly soluble in water or ethanol, insoluble in chloroform or ether. Heat-resistant, but in the case of oxidizing or reducing substances (such as vitamin C or hydrogen peroxide, etc.), heavy metal salts and strong acids, alkalis, it can become invalid.|
|The structure of vitamin B12||Vitamin B12 is octahedral compound containing cobalt ions, its center structure is composed of four pyrrole (pyrrole) connected to the composition of the plane goo phen ring corrinring.Vitamin B12 molecule generally consists of three parts: four N atoms and the central cobalt ion is chelated to Corrin ring; 5,6-dimethylbenzimidazole (5, 6-dimethylbenzimidazole,DMBI) by N-7 atoms and cobalt ions linked to low vitamin B12 molecule as a (alpha) ligand, in addition, DMBI is by phosphate groups and aminopropanol aminopropanol connected and ammonia alcohol and pyrrole D of the propionic acid side chains covalently connected; adenosine (adenosylgroup) or methyl (methylgroup) and cobalt ions linked to vitamin B12 molecules of the host (beta) ligand. Ligands above corrin ring axial are different forms of vitamin B12 substances of different types. The hydroxyl (-OH) is connected with the cobalt Corrin ring in the formation of hydroxocobalamin (hydroxycobalamin), similarly, deoxyadenosine (5 '-deoxyadenosyl), methyl (-CH3), cyano (-CN) connected with cobalt ions each generat to deoxyadenosylcobalamin (deoxyadenosylcobalamin), methyl cobalamin (methylcobalamin) and Vitamin B12e (Vitamin B12). In nature, the final form of vitamin B12 is microbial biosynthesis of deoxyadenosylcobalamin (coenzyme B12), methyl cobalamin and hydroxycobalamin. But because their character is not stable, artificially adding sodium cyanide in industrial purification process, can make the natural form of vitamin B12 into more stable Vitamin B12e.
Figure 2 the structure of vitamin B12
|Uses||1. Vitamin B12 deficiency can cause anemia, nervous system disorders. It can be used in infant foods, used amount is 10~30μg/kg; use in strengthening drink liquid and the amount is 2~6μg/kg.
2. Mainly used to treat megaloblastic anemia, poor nutrition, blood loss anemia, neuralgia and obstructive disorders.
3. As the feed nutrition fortifier, with anti-anemia effects of pernicious anemia, nutritional anemia, parasites and anemia and effective dosage is 15-30mg/t.
4. Vitamin B12 is essential for the metabolism of the human body. The average total amount of vitamin B12 in the human body is 2-5mg, 50-90% of which is stored in the liver, the body needs to release into the blood in the formation of red blood cells. Chronic lack of B12 can cause pernicious anemia. B12 and folic acid are important fear of enzymes during cell nucleic acid synthesis, involved in the synthesis of purines, pyrimidines, nucleic acids and methionine; and allows methyltransferase to promote the synthesis of the base; at the same time to increase the synthesis of sugar yuan, thus eliminating the role of liver fat. Clinical often as a drug for the treatment of liver diseases. Human need vitamin B121 micrograms per day, every day foods provide 2 micrograms, to ensure the normal needs. Hydroxocobalamin in Vitamin B12 reacts with cyanide to generate Vitamin B12, to eliminate cyanide toxicity. Therefore, the lack of vitamin B12 for cyanide sensitivity is higher than the average person. Thus, vitamin B12 deficiency sensitivity to cyanide higher than the average person. Vitamin B12 is mainly used to treat pernicious anemia, megaloblastic anemia, antifolate drugs starting from anemia and multiple neuritis.
|Physiologic function||1. To improve the utilization of folic acid, it and folic acid are together with the synthesis of methionine (from high cysteine synthetase) and choline, producing Vitamin B12 application based pioneer substances such as methyl cobalamin and coenzyme B12 in purine and pyrimidine synthesis process, participating in the methylation process in many important compounds. When vitamin B12 deficiency, activities which transferred methyl groups from the methylenetetrahydrofolate reduced to make folic acid into no use of form, leading to folate deficiency.
2.Maintain the metabolism and function of the nerve myelin sheath. Lack of vitamin B12, can cause neurological disorders, degeneration of spinal cord, and can cause severe psychiatric symptoms. Vitamin B12 deficiency can cause peripheral neuritis. Children's lack of vitamin B12 early performance is emotional, dull, slow response, and finally leads to anemia.
3. Promote the development and maturation of red blood cells. The two acyl coenzyme A is converted to succinate coenzyme A, which is involved in the synthesis of three carboxylic acid cycle, in which the synthesis of A is related to the synthesis of heme.
4. Vitamin B12 is also involved in synthesis of deoxy nucleic acid (DNA), metabolism of fat, carbohydrate and protein, increasing the synthesis of nucleic acids and proteins.
An overview of vitamin B12, traits, physiological function, application are compiled by Eastern of Chemicalbook . (2016-12-10)