Food chemistry and physiological function of pseudovitamin B<sub>12</sub>

  • Tanioka Yuri
    Department of Nutrition, Faculty of Applied Life Science, Tokyo University of Agriculture

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  • シュードビタミンB<sub>12</sub> の生理機能の解明と食品化学的研究
  • シュードビタミンB₁₂の生理機能の解明と食品化学的研究
  • シュードビタミン B ₁ ₂ ノ セイリ キノウ ノ カイメイ ト ショクヒン カガクテキ ケンキュウ

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Vitamin B 12 (B 12 ) is synthesized only in certain bacteria. B 12 is concentrated mainly in the body of the higher predatory organisms in the natural food chain. Animal-derived foods such as meats, shellfish, egg, and milk are good dietary B 12 sources. In addition, a B 12 compound was contained abundantly in edible cyanobacteria. The B 12 compound present in edible cyanobacteria has been identified as pseudovitamin B 12 , an inactive corrinoid compound for humans. Therefore, this study was attempted to clarify the physiological function of pseudovitamin B 12 in cyanobacteria. The full-length of Spirulina B 12 -dependent methionine synthase was cloned into E.coli to clarify the physiological function of pseudovitamin B 12 in cyanobacteria. The recombinant Spirulina enzyme showed a higher affinity for methylpseudovitamin B 12 than methylcobalamin as a cofactor, indicating that cyanobacateria can utilize pseudovitamin B 12 as the cofactor for B 12 -dependent methionine synthase.<br>  It was further examined whether pseudovitamin B 12 exists in dietary sources other than edible cyanobacteria. As a result, a large amount of pseudovitamin B 12 was detected in turban shell and abalone, herbivorous sea snails. The content of B 12 in seaweeds which herbivorous sea snails consume as the food was very low, suggesting that pseudovitamin B 12 detected in herbivorous sea snails might be derived from cyanobacteria adhering to seaweeds.



    VITAMINS 93 (2), 47-51, 2019-02-25


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