Exclusive Expression of Transketolase in the Vanadocytes of the Vanadium-Rich Ascidian, Ascidia sydneiensis samea

Biochimica et biophysica acta 1494 巻 83-90 頁 2000 発行
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Exclusive Expression of Transketolase in the Vanadocytes of the Vanadium-Rich Ascidian, Ascidia sydneiensis samea
作成者
Uyama Taro
Kanamori Kan
Michibata Hitoshi
収録物名
Biochimica et biophysica acta
1494
開始ページ 83
終了ページ 90
抄録
Ascidians, especially those belonging to the Ascidiidae, are known to accumulate extremely high levels of vanadium in vanadocytes, one type of blood (coelomic) cell. Vanadium, which exists in the +5 oxidation state in seawater, is accumulated in the vanadocytes and reduced to the +3 oxidation state. We have been trying to characterize all of the polypeptides specific to vanadocytes and to specify the proteins that participate in the accumulation and reduction of vanadium. To date, we have localized three enzymes in vanadocytes: 6-phosphogluconate dehydrogenase (6-PGDH: EC 1.1.1.44), glucose-6-phosphate dehydrogenase (G6PDH: EC 1.1.1.49), and glycogen phosphorylase (GP: EC 2.4.1.1), all of which are involved in the pentose phosphate pathway. In the current study, we cloned a cDNA for transketolase, an essential and rate-limiting enzyme in the non-oxidative part of the pentose phosphate pathway, from vanadocytes. The cDNA encoded a protein of 624 amino acids, which showed 61.8 0dentity to the human adult-type transketolase gene product. By immunocytochemistry and immunoblot analyses, the transketolase was revealed to be a protein that was expressed only in vanadocytes and not in any of the more than ten other types of blood cell. This finding, taken together with the localized expression of the other three enzymes, strongly supports the hypothesis that the pentose phosphate pathway functions exclusively in vanadocytes.
著者キーワード
Chordates
Metal Accumulation
Redox
Gene Expression
NDC分類
生物科学・一般生物学 [ 460 ]
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 2000
権利情報
Copyright (c) 2000 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] 0167-4781
[NCID] AA10506089
[PMID] 11072071
[DOI] 10.1016/S0167-4781(00)00222-0
[DOI] http://dx.doi.org/10.1016/S0167-4781(00)00222-0 ~の異版である