Cobalamin

Also called vitamin B12. A vitamin important for the normal formation of red blood cells and for the health of the nerve tissues. Undetected and untreated vitamin B12 deficiency can lead to anemia and permanent nerve and brain damage. Pernicious anemia is a blood disorder caused by inadequate vitamin B12 in the blood. Patients who have this disorder do not produce the protein substance in the stomach that allows the body to absorb vitamin B12. This substance is called intrinsic factor (IF). Pernicious anemia is simply treated with injections of vitamin B12. The vitamin B12 has to be administered by injection because people with PA do not have IF (or an effective form of IF) and so cannot absorb vitamin B12 taken by mouth. Pernicious anemia has also been called Addison’s anemia, addisonian anemia, Biermer’s anemia. Patients with Crohn’s disease involving the small intestine (Crohn’s ileitis) or who have undergone small intestine resection may not be able to absorb vitamin B12. Strict vegetarians who consume no animal products can develop B12 deficiency since there is a lack of B12 in vegetables. The recommended daily allowances of vitamin B12 in the United States are 2mcg for infants, 3 mcg for children under 4 years old, 6mcg for children over 4 years old and adults, and 8 mcg for pregnant women. It is recommended for adults to take one multivitamin daily. One multivitamin a day is safe and inexpensive. The multivitamin should contain 400 micrograms of folic acid, approximately 2-3 mg of vitamin B6, 6-9 micrograms of vitamin of B12, and 400 IU of vitamin D. The folic acid and the other B vitamins can help lower homocysteine. The vitamin D is one of the important factors in preventing osteoporosis. High blood homocysteine levels have been found to be a risk factor for atherosclerosis and heart disease. Most doctors will treat homocysteine levels higher than 9-10umol/liter. A doctor experienced in treating coronary heart disease should supervise the treatment of hyperhomocysteinemia. Treatment involves high doses of the B vitamins (1-5 mg/day of folic acid, 10mg/day of B6, and 0.4 mg/day of B12). ALL vitamin supplements, with the exception of vitamin B12 supplement, are chemically synthesized. This means that they are produced by combining separate chemical elements in a factory. Vitamin B12 is biosynthesized, which means that it is made by using bacterial enzymes.

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General term for compounds containing the dimethylbenzimidazolylcobamide nucleus of vitamin B₁₂.

- ATP c. adenoxyltransferase an enzyme that catalyzes the reaction of ATP, water, and c. to form orthophosphate, pyrophosphate, and adenoxylcobalamin. Adenosylcobalamin is required by methylmalonyl-CoA mutase. A deficiency of ATP c. adenosyltransferase will lead to methylmalonic acidemia.

- c. concentrate the dried, partially purified product resulting from the growth of selected Streptomyces cultures or other c.-producing microorganisms; contains at least 500 μg of c. in each gram.

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co·bal·a·min kō-'bal-ə-mən also co·bal·a·mine -.mēn n VITAMIN B₁₂

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n.

see vitamin B12

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co·bal·a·min (ko-balґə-min) 1. in chemical nomenclature, a compound comprising the substituted corrin ring and 5,6-dimethylbenzimidazole–containing nucleotide that are characteristic of vitamin B₁₂, but lacking a ligand at the 6 position of the cobalt. 2. a term used generically to denote any substituted derivative of this compound, including cyanocobalamin, particularly one with vitamin B₁₂ activity.