Folate and cobalamin are necessary for early brain development and function. Deficiency of folate or cobalamin during pregnancy can cause severe malformation in the central nervous system such as neural tube defects. After birth, folate and cobalamin deficiency can cause anemia, failure to thrive, recurrent infections, psychiatric and neurological symptoms. The folate and the homocysteine metab...

UNLABELLED Targeting cancer cells with vitamin B12 (cobalamin) is hampered by unwanted physiologic tissue uptake mediated by transcobalamin. Adhering to good manufacturing practice, we have developed a new (99m)Tc-cobalamin derivative ((99m)Tc(CO)3-[(4-amido-butyl)-pyridin-2-yl-methyl-amino-acetato] cobalamin, (99m)Tc-PAMA-cobalamin). The derivative shows no binding to transcobalamin but is rec...

Vitamin B12 (VB12) is an essential water-soluble vitamin that also known as Cobalamin [1]. It is composed of a corrin ring consisting of four pyrrole units and a cobalt ion at the center of the ring [2]. 1VB12 is manufactured by microorganisms present in the liver of animals bound to protein. The average B12 content of liver tissue is approximately 1.0 microgram/g of tissue in healthy adults [3...

We have read with interest Hvas and Nexo’s very informative update article about the diagnosis and treatment of vitamin B12 deficiency. Authors also stated that vitamin B12 deficiency is an important public health problem. It is well known that diagnostic approach to this deficiency is very important to reveal the underlying cause that is usually attributed to malabsorption. Carmel et al.’s fou...

The challenges in medical management of cobalamin deficiency lie in attention to the unique pathophysiology that underlies cobalamin deficiency, more than in the mechanics of therapy. The central physiologic principles are that clinically important deficiency is more likely to occur (and progress) when intrinsic factor-driven absorption fails than when diet is poor and that most causes take yea...

Cultured fibroblasts from a recently described patient with homocystinuria and megaloblastic anemia of infancy without methylmalonic aciduria were previously shown to have normal cobalamin uptake and a specific decrease in the proportion of intracellular methylcobalamin. As in control cells but unlike in those from patients with combined homocystinuria and methylmalonic aciduria (cobalamin C an...

AIMS To compare the efficacy of sublingual and oral administration of 500 micro g of cobalamin in subjects with cobalamin deficiency. MATERIALS AND RESULTS Thirty subjects with low serum concentrations of cobalamin participated in the study. Subjects were randomly allocated to receive one tablet daily of 500 micro g cobalamin sublingually or orally, or two tablets daily of a vitamin B complex...

n engl j med 367;4 nejm.org july 26, 2012 385 Failures of Cobalamin Assays in Pernicious Anemia To the Editor: Cobalamin (vitamin B12) assays have been central to the diagnosis of clinical cobalamin deficiency such as pernicious anemia because the diagnostic sensitivities of older assays have been approximately 95%.1 However, the competitive-binding luminescence assay (CBLA) replaced older micr...

Cobalamin synthesis probably requires 20 to 30 different enzymatic steps. Pseudomonas putida and Agrobacterium tumefaciens mutants deficient in cobalamin synthesis (Cob have been isolated. In P. putida, Cob mutants were identified as being unable to use ethanolamine as a source of nitrogen in the absence of added cobalamin (deamination of ethanolamine requires coenzyme B12 as a cofactor). In A....

This study describes the identification and the structural and spectroscopic analysis of a cobalamin-binding protein (termed CobDH) implicated in O-demethylation by the organohalide-respiring bacterium Desulfitobacterium hafniense DCB-2. The 1.5 Å resolution crystal structure of CobDH is presented in the cobalamin-bound state and reveals that the protein is composed of an N-terminal helix-bundl...