| Hydrolytic reactions of guanosyl-(3',3')-uridine and guanosyl-(3',3')-(2',5'-di-O-methyluridine). | |
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MedLine Citation:
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PMID: 15339190 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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Hydrolytic reactions of guanosyl-(3',3')-uridine and guanosyl-(3',3')-(2',5'-di-O-methyluridine) have been followed by RP HPLC over a wide pH range at 363.2 K in order to elucidate the role of the 2'-hydroxyl group as a hydrogen-bond donor upon departure of the 3'-uridine moiety. Under neutral and basic conditions, guanosyl-(3',3')-uridine undergoes hydroxide ion-catalyzed cleavage (first order in [OH(-)]) of the P-O3' bonds, giving uridine and guanosine 2',3'-cyclic monophosphates, which are subsequently hydrolyzed to a mixture of 2'- and 3'-monophosphates. This bond rupture is 23 times as fast as the corresponding cleavage of the P-O3' bond of guanosyl-(3',3')-(2',5'-di-O-methyluridine) to yield 2',5'-O-dimethyluridine and guanosine 2',3'-cyclic phosphate. Under acidic conditions, where the reactivity differences are smaller, depurination and isomerization compete with the cleavage. The effect of Zn(2+) on the cleavage of the P-O3' bonds of guanosyl-(3',3')-uridine is modest: about 6-fold acceleration was observed at [Zn(2+)] = 5 mmol L(-)(1) and pH 5.6. With guanosyl-(3',3')-(2',5'-di-O-methyluridine) the rate-acceleration effect is greater: a 37-fold acceleration was observed. The mechanisms of the partial reactions, in particular the effects of the 2'-hydroxyl group on the departure of the 3'-linked nucleoside, are discussed. |
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Authors:
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Anu Kiviniemi; Tuomas Lönnberg; Mikko Ora |
Publication Detail:
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Type: Journal Article |
Journal Detail:
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Title: Journal of the American Chemical Society Volume: 126 ISSN: 0002-7863 ISO Abbreviation: J. Am. Chem. Soc. Publication Date: 2004 Sep |
Date Detail:
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Created Date: 2004-09-01 Completed Date: 2004-11-10 Revised Date: - |
Medline Journal Info:
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Nlm Unique ID: 7503056 Medline TA: J Am Chem Soc Country: United States |
Other Details:
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Languages: eng Pagination: 11040-5 Citation Subset: IM |
Affiliation:
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Contribution from the Department of Chemistry, University of Turku, FIN-20014 Turku, Finland. |
Export Citation:
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APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
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Guanosine
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analogs & derivatives*,
chemistry Hydrogen Bonding Hydrogen-Ion Concentration Hydrolysis Kinetics Phosphoric Acid Esters / chemistry Uridine / analogs & derivatives*, chemistry Zinc / chemistry |
| Chemical | |
Reg. No./Substance:
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0/Phosphoric Acid Esters; 118-00-3/Guanosine; 58-96-8/Uridine; 7440-66-6/Zinc |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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