Vitamin B12

Vitamin B

Vitamin B12 is the largest and most complex of all vitamins. it is unique among vitamins In that it contains a metal ion, cobalt. For this reason cobalamin is the term used to refer to compound h 727i810h aving B12 activity.

Vitamin B12 is complex tetra-pyrrol ring structure and a cobalt ion in the middle. the vitamin must be hydrolyzed from protein in order to be active.

Methylcobalamin and 5-deoxyadenosyl cobalamin are the forms of vitamin B12 used the human body.

The form of cobalamin used in most supplements, cyanocobalamine (complex water-soluble organic compound), is readily converted to 5-deoxyadenosyl and methylcobalamine, two active coenzymes that involved in cellular metabolism.

Vitamin B12 is also known as the anti-pernicious-anemia factor.

Function:

Cofactor for methionine synthesis

Methylcobalamine is required for the function of the folate dependent enzyme, methionine syntheses .this enzyme is required for the synthesis of the amino acids, methionine, and form homocysteine. Methionine is required for the synthesis of S-adenosylmethionine, a methyl group donor used in many biological methylation reactions, including the methylation of number of sites within DNA and RNA. Methylation of DNA may be important in cancer prevention.

The S-adenosylmethionine or sAMe is presently classes with glucose amine and condroitin as a potential "chondroprotective" agent, one that slowing the progression of arthritis.

Vitamin B12 is required for the normal activity of nerve cells, and works with folate and vitamin B6 to lower blood levels of homocysteine.

Inadequate function of methionine syntheses can lead to an accumulation of homocysteine, which has been associated with increased risk of cardiovascular diseases.

Cofactor for L-mthylmalonyl-CoA mutase

5-deoxyadenosylcobalamine is required by the enzyme that catalyze the conversion of L-methylmalonyl-CoA to succinyl-CoA.this biochemical reaction play an important role in the production of energy from fats and proteins .succinyl-CoA is also required for the synthesis of hemoglobin, the oxygen caring piggament in red blood cells.

Vitamin B12 has also separate biochemical role,in the synthesis of fatty acids in the myeline sheath that surrounds the nerve cells.

Recent evidence suggest that B12 supplements may improve sperm count and mobility,possibly enhancing fertilization.

Deficiency: