ビタミンKの生体内代謝機構に関する研究

• 廣田　 佳久

  芝浦工業大学　システム理工学部　生命科学科

書誌事項

タイトル別名

• Study on Mechanism Underlying Metabolic Biotransformation of Vitamin K
• ビタミン K ノ セイタイナイ タイシャ キコウ ニ カンスル ケンキュウ

抄録

The vitamin K family comprises vitamin K₁ (phylloquinone [PK]) derived from plants, vitamin K₂ (menaquinone-n [MK-n]) from intestinal bacteria, and vitamin K₃ (menadione [MD]) derived synthetically without a bioactive side chain. Diet-derived vitamin K mainly comprises PK but menaquinone-4 (MK4) is predominantly found in tissues. It has been predicted that PK undergoes a transformation to MK-4 in tissues, resulting in MK-4 accumulation within the tissues. However, the mechanism underlying this biotransformation has remained unknown for more than 60 years. Hence, we aimed to elucidate the mechanism underlaying the metabolic biotransformation of vitamin K. 　Diet-derived vitamin K is partly absorbed by the lymphatic vessels in small intestinal villi, i.e., lacteals, and most of it is metabolized to MD by a side-chain cleavage enzyme in the small intestine, although this enzyme has been thought to be present in the tissue. The MD thus transformed from vitamin K is transported from the lymphatic vessels to all tissues via systemic circulation. We previously reported that MD is transformed to MK-4 by UbiA prenyltransferase domain containing protein 1 (UBIAD1) present in each tissue. The MK-4 thus transformed from MD acts as a biologically active vitamin K and exerts various physiological functions such as blood coagulation and bone formation via vitamin K-dependent gamma-carboxylase (GGCX), steroid and xenobiotic receptor (SXR), and protein kinase A (PKA) signaling. Therefore, we have proposed that MK-4 is no longer within a vitamin framework and that it has physiologically and nutritionally important hormone-like functions. Thus, we have successfully elucidated a part of the mechanism undelaying the metabolic biotransformation of vitamin K.

収録刊行物

• ビタミン

  ビタミン 92 (2), 63-72, 2018-02-25

  公益社団法人 日本ビタミン学会

キーワード

• Vitamin K
• phylloquinone
• menaquinone
• menadione
• metabolic biotransformation
• UBIAD1

詳細情報

• CRID: 1390845713054558336
• NII論文ID: 130007605076
• NII書誌ID: AN00207833
• DOI: 10.20632/vso.92.2_63
• ISSN: 2424080X
• ISSN: 0006386X
• NDL書誌ID: 028870173
• Web Site: https://ndlsearch.ndl.go.jp/books/R000000004-I028870173
• Web Site: https://search.jamas.or.jp/link/ui/2018126820
• 本文言語コード: ja
• データソース種別:
  • JaLC
  • NDL
  • CiNii Articles
• 抄録ライセンスフラグ: 使用不可