Ferredoxin-Sulfite Reductase of Allium odorum   :   ニラのフェレドキシン-亜硫酸還元酵素 

作成者 Tamura, Goro, Hosoi, Tamioki, Asada, Hiroshi
作成者 (ヨミ) タムラ, ゴロウ, ホソイ, タミオキ, アサダ, ヒロシ
作成者の別表記 田村, 五郎, 細井, 民興, 浅田, 宏
日本十進分類法 (NDC) 620
内容 ニラの緑葉中に, フェレドキシンの還元型を電子供与体とする亜硫酸還元酵素を見出した.この酵素をトリス硫酸緩衝液を用いて抽出し, アセトン分画(0〜50%)により濃縮した.この酵素の活性は, 基質である亜硫酸塩及び電子供与体である還元型フェレドキシンの濃度に依存し, それぞれ飽和曲線を示した.この酵素の亜硫酸還元反応における最適pHは, 7.5〜8.0である.植物は硫酸を根より吸収して葉におくり, ここで亜硫酸を生じ, さらに還元して硫化水素に変え, 炭素骨骼と結合せしめてシステインを生合成する.ここに報告したフェレドキシン-亜硫酸還元酵素は, まさにこの亜硫酸→硫化水素の反応に関与している酵素であると考えられる.
Ferredoxin-Sulfite Reductase of Allium odorum. Goro TAMURA, Tamioki HOSOI and Hiroshi ASADA. Faculty of Horticulture, Chiba University, Matsudo, Japan. Tech. Bull. Fac. Hort. Chiba Univ., No.26 : 35-38, 1979. Ferredoxin-sulfite reductase from Allium odorum leaves was extracted and partially purified by acetone fractionation (0-50%). The optimum pH of the enzyme was 7.5 to 8.0 in Tris-H_2SO_4 buffer. The enzymatic activity was dependent on the concentration of sulfite and ferredoxin providing each saturation curves. The enzyme catalyzed the conversion of sulfite to sulfide, both of which have been known as intermediates in plant-type biosynthesis of cysteine from sulfate. Recent studies of assimilatory sulfate reduction in higher plants have shown that sulfite is reduced to the level of sulfide according to the following equation (TAMURA, 1976). [numerical formula] Involved in this reaction as an indispensable component is sulfite reductase (SiR) (TAMURA, 1965). Photoreduced ferredoxin (Fd・) has been reported to be a physiological electron donor in this reductase system (TAMURA and ITOH, 1974). Although methyl viologen-linked SiR [hydrogen-sulfide: (acceptor) oxidoreductase, EC] of Allium odorum, Spinacea oleracea and Porphyra yezoensis have been highly purified and extensively characterized, none of these purified enzymes have been demonstrated to be able to couple with reduced ferredoxin (TAMURA, 1976). In this paper we show that ferredoxin-sulfite reductase (Fd・-SiR) [hydrogen-sulfide: ferredoxin oxidoreductase, EC] is present in leaf extracts from Allium odorum.

公開者 千葉大学園芸学部
コンテンツの種類 紀要論文 Departmental Bulletin Paper
DCMI資源タイプ text
ファイル形式 application/pdf
ISSN 0069-3227
NCID AN00142658
掲載誌情報 千葉大学園芸学部学術報告 Vol.26 page.35-38 (19790228)
情報源 The technical bulletin of Faculty of Horticulture, Chiba University
言語 英語
著者版フラグ publisher

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