Cellular Import of Cobalamin (Vitamin B-12)
نویسندگان
چکیده
منابع مشابه
Cobalamin (vitamin B(12)) biosynthesis in Rhodobacter capsulatus.
In Rhodobacter capsulatus, cobalamin biosynthesis has been shown to occur when the bacteria are grown either aerobically or anaerobically. However, a comparison of the main cobalamin biosynthetic operon found within R. capsulatus would suggest that the encoded proteins belong to the oxygen-dependent pathway for cobalamin biosynthesis, although, significantly, no homologue of the essential mono-...
متن کاملMetabolic evidence that deficiencies of vitamin B-12 (cobalamin), folate, and vitamin B-6 occur commonly in elderly people.
Measurements of the serum concentrations of the metabolites homocysteine, cystathionine, methylmalonic acid, and 2-methylcitric acid, which accumulates when vitamin B-12-, folate-, and vitamin B-6-dependent enzymatic reactions are impaired, should provide a better indication of intracellular deficiency of these vitamins. We measured the serum concentration of these vitamins and the four metabol...
متن کاملCobalamin and folate evaluation: measurement of methylmalonic acid and homocysteine vs vitamin B(12) and folate.
Vitamin B(12) and folate are two vitamins that have interdependent roles in nucleic acid synthesis. Deficiencies of either vitamin can cause megaloblastic anemia; however, inappropriate treatment of B(12) deficiency with folate can cause irreversible nerve degeneration. Inadequate folate nutrition during early pregnancy can cause neural tube defects in the developing fetus. In addition, folate ...
متن کاملVitamin B-12.
V itamin B-12 is a cofactor for 2 enzymes. In the cytoplasm, methionine synthase requires vitamin B-12 in the form of methylcobalamin and catalyzes the conversion of homocysteine to methi-onine by transfer of a methyl group from methyltet-rahydrofolate. This enzyme links the methylation pathway through synthesis of the methyl donor S-adenosyl methionine and the pathway in which purine and pyrim...
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ژورنال
عنوان ژورنال: The Journal of Nutrition
سال: 1999
ISSN: 0022-3166,1541-6100
DOI: 10.1093/jn/129.10.1761