鉄を調節する鉄還元酵素で,食中の鉄の吸収に関連しています
A T McKie1, D Barrow, G O Latunde-Dada
1Department of Molecular Medicine, Guy's, King's and St. Thomas' School of Medicine, King's College London, Rayne Institute, Denmark Hill Campus, 123 Coldharbour Lane, London SE5 9NU, UK. andrew.t.mckie@kcl.ac.uk
まとめ
研究者らは,鉄の吸収に不可欠なタンパク質である十二指管細胞染色体b (Dcytb) を特定した. この発見は,腸内の鉄還元酵素の活性と鉄の状態の調節に関する理解を深める.
科学分野:
- バイオケミストリー バイオケミストリー
- 分子生物学は分子生物学である.
- 胃腸内科 胃腸内科
背景:
- 腸内の鉄の吸収は,鉄の恒常性を維持するために不可欠です.
- 食中の鉄酸鉄の吸収は,ブラッシュ・ボーダー膜還元酵素の活性に依存する.
- この還元酵素の活動は,体の鉄の状態に対する適応反応を示しています.
研究 の 目的:
- 腸内鉄の吸収に関与する重要な還元酵素をコードする補完DNA (cDNA) を分離し,特徴づけること.
- このタンパク質が鉄還元酵素の活性と鉄の状態によるその調節における役割を調査する.
主な方法:
- マウスの十二指管粘膜から十二指管サイトクロームb (Dcytb) の補完DNA (cDNA) の分離.
- 既知のサイトクロームb561ファミリーメンバーとのDcytb配列類似性の分析.
- 機能的還元酵素活性を評価するために,Xenopusの卵細胞と培養細胞での発現研究.
- 異なる鉄吸収条件下でDcytbメッセンジャーRNAとタンパク質のレベルを定量化する.
主要な成果:
- プラズマ膜の二ヘムタンパク質をコードする新しいcDNA,Dcytbが分離されました.
- Dcytbは,プラズマ膜還元酵素のサイトクロームb561ファミリーと有意な類似性を示しています.
- Dcytbは,十二指腸腸細胞のブラシ境界膜に高度に発現しています.
- 卵細胞と培養細胞におけるDcytbの発現は,鉄還元酵素活性を引き起こす.
- 十二指管のDcytb発現レベルは,鉄吸収の生理学的調節剤によって調節された.
結論:
- Dcytbは,腸内鉄吸収経路の重要な成分として特定されています.
- このタンパク質は,ブラッシュ・ボーダー膜フェリック還元酵素として機能している可能性が高い.
- Dcytbの発現は鉄の状態によって調節され,適応性鉄吸収に貢献します.
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