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Titolo:
Rate constants of ozone reactions with DNA, its constituents and related compounds
Autore:
Theruvathu, JA; Flyunt, R; Aravindakumar, CT; von Sonntag, C;
Indirizzi:
Max Planck Inst Strahlenchem, D-45413 Mulheim, Germany Max Planck Inst Strahlenchem Mulheim Germany D-45413 13 Mulheim, Germany
Titolo Testata:
JOURNAL OF THE CHEMICAL SOCIETY-PERKIN TRANSACTIONS 2
fascicolo: 3, , anno: 2001,
pagine: 269 - 274
SICI:
1472-779X(2001):3<269:RCOORW>2.0.ZU;2-2
Fonte:
ISI
Lingua:
ENG
Soggetto:
ELECTRON-REDUCTION POTENTIALS; MAIN OXIDATION-PRODUCTS; FREE PHOSPHATE BUFFER; CALF-THYMUS DNA; AQUEOUS-SOLUTION; NUCLEIC-ACIDS; COMPARATIVE INACTIVATION; ESCHERICHIA-COLI; PULSE-RADIOLYSIS; INDIGO METHOD;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Physical, Chemical & Earth Sciences
Citazioni:
66
Recensione:
Indirizzi per estratti:
Indirizzo: von Sonntag, C Max Planck Inst Strahlenchem, Stiftstr 34-36,POB 101365, D-45413 Mulheim, Germany Max Planck Inst Strahlenchem Stiftstr 34-36,POB 101365 Mulheim Germany D-45413
Citazione:
J.A. Theruvathu et al., "Rate constants of ozone reactions with DNA, its constituents and related compounds", J CHEM S P2, (3), 2001, pp. 269-274

Abstract

The rate constants of the reaction of ozone with DNA, its constituents andrelated compounds have been determined as a function of pH by competition with nitrite and/or buten-3-ol and, when the rate constant was less than orequal to 10(3) dm(3) mol(-1) s(-1), by the indigo method. Depending on thedegree of protonation, the rate constant (in units of dm(3) mol(-1) s(-1))varies substantially, e.g. in the case of cytosine, k = 18 (protonated), k= 1.4 x 10(3) (neutral) and k = 1.5 x 10(6) (deprotonated). A similar variation has been found with the other nucleobases. Upon deprotonation the mechanism of the ozone reaction may also change; e.g. no singlet dioxygen (O-2(1)Delta (g)) is formed in its reaction with 5-chlorouracil, but when the 5-chlorouracilate ion predominates it becomes a major product (similar to 42%). Rate constants for the neutral compounds are: thymine (4.2 x 10(4)), thymidine (3.0 x 10(4)), 1,3-dimethyluracil (2.8 x 10(3)), uracil (650), 6-methyluracil (140), 5-chlorouracil (4.3 x 10(3)), orotic acid (5.9 x 10(3)),isoorotic acid (3.7 x 10(3)), 2'-deoxycytidine (3.5 x 10(3)), cytidine (3.5 x 10(3)), adenine (12), 2'-deoxyadenosine (14), adenosine (16), guanosine(1.6 x 10(4)), 2'-deoxyguanosine (1.9 x 10(4)) and DNA (410). In the case of adenine and its derivatives, and thus also in the case of DNA, (OH)-O-. is produced (via O-2(.-) as an intermediate). For the determination of their intrinsic ozone rate constants, tert-butyl alcohol was added as the (OH)-O-. scavenger.

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Documento generato il 26/05/20 alle ore 05:13:10