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ID 7
Eprint ID
7
フルテキストURL
タイトル(別表記)
ATP-citrate Lyase: The key enzyme of the reductive TCA cycle
著者
金尾 忠芳 岡山大学
抄録
Almost all organic compounds which construct life are derived from carbon dioxide (CO2) assimilated by autotrrophic organisms.The reductive tricarboxylic acid (RTCA) cycle functions as a carbon dioxide fixation pathway, distinct from Calvin cycle, in a green sulfur bacterium Chlorobium limicola. ATP-citrate lyase (ACL) is one of the key enzymes of this cycle. The enzyme of C. limicola (Cl-ACL) was encoded in two adjacent open reading frames, aclB(1197bp) and aclA(1827bp), whose products showed signficant similarity to the N- and C-terminal regions of the human enzyme, respectively. Heterologous expression of these genes in Escherichia coli proved that both gene products were essential for ACL activity. Kinetic examination of the enzyme revealed that the enzyme displayed typical Michaelis-Monten kinetics toward ATP with an apparent Km value of 0.19mM. However, strong negative cooperativity was observed with respect to citrate binding. ADP was a competitive inhibitor of ATP with a Kj value of 0.036mM. Together with the feature that the enzyme catalyzed the reaction only in the direction of citrate cleavage, these kinetic properties indicated that Cl-ACL can regulate both the direction and carbon flux of the RTCA cycle in C. limicola.
キーワード
CO2 fixation
Reductive TCA cycle
ATP-citrate lyase
発行日
2005-02-01
出版物タイトル
岡山大学農学部学術報告
出版物タイトル(別表記)
Scientific reports of the Faculty of Agriculture, Okayama University
94巻
1号
出版者
岡山大学農学部
出版者(別表記)
Faculty of Agriculture,Okayama University
開始ページ
39
終了ページ
45
ISSN
0474-0254
NCID
AN00033029
資料タイプ
紀要論文
言語
Japanese
論文のバージョン
publisher
査読
無し
Eprints Journal Name
srfa