کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
5376575 | 1504327 | 2007 | 8 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Charge transfer from 2-aminopurine radical cation and radical anion to nucleobases: A pulse radiolysis study
دانلود مقاله + سفارش ترجمه
دانلود مقاله ISI انگلیسی
رایگان برای ایرانیان
کلمات کلیدی
موضوعات مرتبط
مهندسی و علوم پایه
شیمی
شیمی تئوریک و عملی
پیش نمایش صفحه اول مقاله
چکیده انگلیسی
Pulse radiolysis study has been carried out to investigate the properties of the radical cation of 2-aminopurine (2AP) and the probable charge transfer from the radical cation and radical anion of 2AP to natural nucleobases in aqueous medium. The radical cation of 2AP was produced by the reaction of sulfate radical anion (SO4-). The time resolved absorption spectra obtained by the reaction of SO4- with 2AP at neutral pH have two distinct maxima at 380 and 470Â nm and is assigned to the formation of a neutral radical of the form 2AP-N2(-H) (k2Â =Â 4.7Â ÃÂ 109Â dm3Â molâ1Â sâ1 at pH 7). This neutral radical is formed from the deprotonation reaction of a very short-lived radical cation of 2AP. The transient absorption spectra recorded at pH 10.2 have two distinct maxima at 400 and 480Â nm and is assigned to the formation of a nitrogen centered radical (2AP-N(9)). As the hole transport from 2AP to guanine is a highly probable process, the reaction of SO4- is carried out in the presence of guanosine, adenosine and inosine. The spectrum obtained in the presence of guanosine was significantly different from that in the absence and it showed prominent absorption maxima at 380 and 470Â nm, and a weak broad maximum centered around 625Â nm which match well with the reported spectrum of a neutral guanine radical (G(-H)). The electron transfer reaction from the radical anion of 2AP to thymine (T), cytidine (Cyd) and uridine (Urd) was also investigated at neutral pH. Among the three pyrimidines, only the transient spectrum in the presence of T gave a significant difference from the spectral features of the electron adduct of 2AP, which showed a prominent absorption maximum at 340Â nm and this spectrum is similar to the electron adduct spectrum of T. The preferential reduction of thymine by 2APâ and the oxidation of guanosine by 2AP+ clearly follow the oxidation/reduction potentials of the purines and pyrimidines.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Chemical Physics - Volume 331, Issues 2â3, 8 January 2007, Pages 351-358
Journal: Chemical Physics - Volume 331, Issues 2â3, 8 January 2007, Pages 351-358
نویسندگان
P. Manoj, H. Mohan, J.P. Mittal, V.M. Manoj, C.T. Aravindakumar,