このエントリーをはてなブックマークに追加
ID 48772
本文ファイル
著者
Wakai, Satoshi
Kidokoro, Shun-ichi
Masaki, Kazuo
Nakasone, Kaoru
Sambongi, Yoshihiro 大学院生物圏科学研究科 広大研究者総覧
抄録(英)
A decrease in water activity was thought to result in smaller enthalpy change values during PPi hydrolysis, indicating the importance of solvation for the reaction. However, the physiological significance of this phenomenon is unknown. Here, we combined biochemistry and calorimetry to solve this problem using NaCl, a physiologically occurring water activity-reducing reagent. The pyrophosphatase activities of extremely halophilic Haloarcula japonica, which can grow at ∼4 m NaCl, and non-halophilic Escherichia coli and Saccharomyces cerevisiae were maximal at 2.0 and 0.1 m NaCl, respectively. Thus, halophilic and non-halophilic pyrophosphatases exhibit distinct maximal activities at different NaCl concentration ranges. Upon calorimetry, the same exothermic enthalpy change of −35 kJ/mol was obtained for the halophile and non-halophiles at 1.5–4.0 and 0.1–2.0 m NaCl, respectively. These results show that solvation changes caused by up to 4.0 m NaCl (water activity of ∼0.84) do not affect the enthalpy change in PPi hydrolysis. It has been postulated that PPi is an ATP analog, having a so-called high energy phosphate bond, and that the hydrolysis of both compounds is enthalpically driven. Therefore, our results indicate that the hydrolysis of high energy phosphate compounds, which are responsible for biological energy conversion, is enthalpically driven within the physiological limits of NaCl.
内容記述
This work was supported by Grant-in-aid for Scientific Research on Innovative Areas 20118005 from the Ministry of Education, Culture, Sports, Science, and Technology of Japan.
掲載誌名
Journal of Biological Chemistry
288巻
41号
開始ページ
29247
終了ページ
29251
出版年月日
2013-10-11
出版者
The American Society for Biochemistry and Molecular Biology, Inc.
ISSN
0021-9258
1083-351X
出版者DOI
言語
英語
NII資源タイプ
学術雑誌論文
広大資料タイプ
学術雑誌論文
DCMIタイプ
text
フォーマット
application/pdf
著者版フラグ
publisher
権利情報
This research was originally published in the Journal of Biological Chemistry. Satoshi Wakai, Shun-ichi Kidokoro, Kazuo Masaki, Kaoru Nakasone, and Yoshihiro Sambongi. Constant Enthalpy Change Value during Pyrophosphate Hydrolysis within the Physiological Limits of NaCl. J Biol Chem. 2013; 288:29247-29251. © 2013 the American Society for Biochemistry and Molecular Biology, Inc.
関連情報URL
部局名
生物圏科学研究科