HYDROLYSIS OF ADENOSINE - A SEMIEMPIRICAL AND AB-INITIO STUDY

Citation
M. Hotokka et H. Lonnberg, HYDROLYSIS OF ADENOSINE - A SEMIEMPIRICAL AND AB-INITIO STUDY, Journal of molecular structure. Theochem, 363(2), 1996, pp. 191-201
Citations number
24
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Chemistry Physical
ISSN journal
0166-1280
Volume
363
Issue
2
Year of publication
1996
Pages
191 - 201
Database
ISI
SICI code
0166-1280(1996)363:2<191:HOA-AS>2.0.ZU;2-X
Abstract
The electron distributions, proton affinities and energies of the hete rolytic fission of the N-glycosidic bond of adenosine, 3-methyladenosi ne and a set of related model compounds have been calculated by semiem pirical and ab initio methods. In the gas phase the preferred site of protonation in adenosine is nitrogen N3 of the adenine ring, the N1 si te being almost as basic. In solution solvent effects change the order , making N7 the preferred protonation site. The 3-methyladenosinium io n is most likely protonated at N7. The net atomic charges of the skele ton atoms, in particular in the N-glycosidic bond, are not markedly af fected by protonation (or by N3 methylation). Yet the electron density of this bond is decreased and the bond is hence weakened. The influen ce is most prominent with the monocations obtained by N7 protonation o r N3 methylation. The previously reported variations of reaction rates are discussed on the basis of these results.