カワムラ　クニオ   KAWAMURA Kunio   川村　邦男    所属   広島修道大学  人間環境学部    職種   教授
言語種別	英語
発行・発表の年月	2003/02
形態種別	学術論文
査読	査読有り
標題	Kinetics and activation parameter analyses of hydrolysis and interconversion of 2',5'- and 3',5'-linked dinucleoside monophosphate at extremely high temperatures
執筆形態	単著
掲載誌名	Biochim. Biophys. Acta
掲載区分	国外
巻・号・頁	1620(1-3),pp.199-210
概要	Kinetic analysis of hydrolytic stability of 2',5'- and 3',5'-linked dinucleoside monophosphate was successfully　performed in aqueous solution at 175–240 oC using a new real-time monitoring method for rapid hydrothermal reactions. The half-lives of　NpN were in the range 2 – 8 s at 240 oC and apparent activation energy decreases in the order U2'pU>A2'pA>G2'pG>U3pU ~ C3'pC>A3'pA.The interconversion of 2',5'-adenylyladenosine monophosphate and 3',5'-adenylyladenosine monophosphate was enhanced in the presence of D- or L-histidine. Kinetic analysis supports the mechanism that imidazolium ion and imidazole catalyze interconversion and hydrolysis even under hydrothermal environments. The activation parameters for the hydrolysis and interconversion of NpN were systematically determined for the first time from the temperature dependence of the rate constants. These parameters support the pseudorotation mechanism through pentacoordinate intermediate from 2',5'- and 3',5'-linked NpN.