Non-covalent intercalative binding of 7,8-dihydroxy-9,10-epoxybenzo(a)pyrene to DNA. [Calf thymus DNA]
- New York Univ., NY
When the benzo(a)pyrene diol epoxide (+) -7..beta..,8..cap alpha..-dihydroxy-9..cap alpha..,10..cap alpha..-epoxy-7,8,9,10-tetrahydrobenzo(a)pyrene (BPDE) is mixed into a DNA solution, a 10nm red shift in the absorption maximum of BPDE appears at 354nm which is due to a non-covalent intercalation complex. The major reaction pathway at this intercalation site is the hydrolysis of BPDE to its tetraol which is accompanied by a decrease in the absorbance and a shift from 354 to 353nm (the latter is due to intercalated tetraol). The non-covalent binding constants are approximately 8200M/sup -1/ for BPDE and 3300M/sup -1/ for the tetraol at 25/sup 0/C, pH 7.0. Covalent adduct formation between BPDE and DNA occurs either at another, external binding site, or after some rearrangement of the intercalated BPDE, since covalent adducts display a 345nm absorption maximum (2nm red shift only).
- OSTI ID:
- 5294154
- Journal Information:
- Biochem. Biophys. Res. Commun.; (United States), Journal Name: Biochem. Biophys. Res. Commun.; (United States) Vol. 100:4; ISSN BBRCA
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
ABSORPTION SPECTRA
ABSORPTION SPECTROSCOPY
ADDUCTS
AROMATICS
BENZOPYRENE
BIOCHEMICAL REACTION KINETICS
CARCINOGENESIS
COMPLEXES
CONDENSED AROMATICS
DNA
HYDROCARBONS
KINETICS
METABOLITES
NUCLEIC ACIDS
ORGANIC COMPOUNDS
PATHOGENESIS
REACTION KINETICS
SPECTRA
SPECTRAL SHIFT
SPECTROSCOPY