Molecular biological approaches to the accumulation and reduction of vanadium by ascidians

Coordination chemistry reviews 237 巻 1-2 号 41-51 頁 2003 発行
アクセス数 : 1506
ダウンロード数 : 271

今月のアクセス数 : 2
今月のダウンロード数 : 3
ファイル情報(添付)
CoordChemRev_234_41-51_2003.pdf 539 KB 種類 : 全文
タイトル ( eng )
Molecular biological approaches to the accumulation and reduction of vanadium by ascidians
作成者
Michibata Hitoshi
Yamaguchi Nobuo
Uyama Taro
収録物名
Coordination chemistry reviews
237
1-2
開始ページ 41
終了ページ 51
抄録
About 90 years ago, Henze discovered high levels of vanadium in the blood (coelomic) cells of an ascidian collected from the Bay of Naples. His discovery attracted the interdisciplinary attention of chemists, physiologists, and biochemists. Two decades ago, we quantified the vanadium levels in several ascidian tissues definitively using neutron-activation analysis and revealed that some species in the family Ascidiidae accumulate vanadium at concentrations in excess of 350 mM, corresponding to about 107 times that found in seawater. Vanadium accumulated is reduced to the +3 oxidation state via the +4 oxidation state and stored in vacuoles of vanadocytes (vanadium-containing blood cells) where high levels of protons and sulfate are also contained. To investigate this unusual phenomenon, we isolated several proteins and genes that are expressed in vanadocytes. To date, three types of vanadium-binding protein, designated as Vanabins, have been isolated, with molecular masses of 12.5, 15, and 16 kDa, along with the cDNAs encoding these proteins. In addition, four types of enzyme related to the pentose phosphate pathway that produces NADPH were revealed to be located in vanadocytes. The pentose phosphate pathway participates in the reduction of vanadium(V) to vanadium(IV). The cDNA for each of the vacuolar-type H+-ATPase (V-ATPase) A, B, C, and D subunits, which are located on the vacuolar membranes of vanadocytes, has been isolated and analyzed. V-ATPase generates a proton-motive force, and is thought to provide the energy for vanadium accumulation.To clarify the entire mechanism involved in the accumulation and reduction, much more genes and proteins expressed in the blood cells need to be systematically identified. Thus, we have performed an expressed sequence tag (EST) analysis of blood cells and have established the functional assay system to elucidate the functions of genes and proteins obtained from ascidian blood cells.
著者キーワード
Ascidian
Tunicate
Vanadium
Accumulation
Reduction
Metalbinding protein
NDC分類
化学 [ 430 ]
言語
英語
資源タイプ 学術雑誌論文
出版者
Elsevier Science B.V.
発行日 2003
権利情報
Copyright (c) 2002 Elsevier Science B.V.
出版タイプ Author’s Original(十分な品質であるとして、著者から正式な査読に提出される版)
アクセス権 オープンアクセス
収録物識別子
[ISSN] 0010-8545
[DOI] 10.1016/S0010-8545(02)00278-3
[DOI] http://dx.doi.org/10.1016/S0010-8545(02)00278-3 ~の異版である