Biomaterial Database

Physical interactions of isomeric benzo [a] pyrene diol-epoxides with DNA. 1982

M C MacLeod, and J K Selkirk

The physical interactions of two diol-epoxides derived from benzo [a] pyrene (B[a]P), 7,8-dihydroxy-9,10-oxy-7,8,9,10-tetrahydro B[a]P (BPDE) and 9,10-dihydroxy-7,8-oxy-7,8,9,10-tetrahydro B[a]P, (reverse BPDE) with DNA have been studied in a simple, in vitro system. The effects of DNA on the rates of hydrolysis of BPDE and reverse BPDE were studied by fluorescence spectroscopy. For both compounds, interaction with DNA was indicated by an increase in the rate of hydrolysis in the presence of DNA. This increased hydrolysis was more marked for BPDE than for reverse BPDE. Direct confirmation of physical binding was obtained by u.v. spectroscopy, where a 10 nm redshift in absorbance maxima characteristic of polycyclic aromatic hydrocarbon.DNA intercalation complexes was observed. Using absorbance changes to monitor binding, association constants of 6580 L/mol and 5080 L/mol were determined for BPDE and reverse BPDE, respectively. Consistent with the intercalation model, binding was inhibited by low concentrations of Mg2+. The enhancement of hydrolytic rate by DNA for BPDE and reverse BPDE was also inhibited by low concentrations of Mg2+, suggesting involvement of intercalation complexes in the mechanism of enhanced hydrolysis.

UI	MeSH Term	Description	Entries
D007536	Isomerism	The phenomenon whereby certain chemical compounds have structures that are different although the compounds possess the same elemental composition. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 5th ed)	Isomerisms
D007700	Kinetics	The rate dynamics in chemical or physical systems.
D008274	Magnesium	A metallic element that has the atomic symbol Mg, atomic number 12, and atomic weight 24.31. It is important for the activity of many enzymes, especially those involved in OXIDATIVE PHOSPHORYLATION.
D009690	Nucleic Acid Conformation	The spatial arrangement of the atoms of a nucleic acid or polynucleotide that results in its characteristic 3-dimensional shape.	DNA Conformation,RNA Conformation,Conformation, DNA,Conformation, Nucleic Acid,Conformation, RNA,Conformations, DNA,Conformations, Nucleic Acid,Conformations, RNA,DNA Conformations,Nucleic Acid Conformations,RNA Conformations
D004247	DNA	A deoxyribonucleotide polymer that is the primary genetic material of all cells. Eukaryotic and prokaryotic organisms normally contain DNA in a double-stranded state, yet several important biological processes transiently involve single-stranded regions. DNA, which consists of a polysugar-phosphate backbone possessing projections of purines (adenine and guanine) and pyrimidines (thymine and cytosine), forms a double helix that is held together by hydrogen bonds between these purines and pyrimidines (adenine to thymine and guanine to cytosine).	DNA, Double-Stranded,Deoxyribonucleic Acid,ds-DNA,DNA, Double Stranded,Double-Stranded DNA,ds DNA
D006868	Hydrolysis	The process of cleaving a chemical compound by the addition of a molecule of water.
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia
D001580	Benzopyrenes	A class of chemicals that contain an anthracene ring with a naphthalene ring attached to it.	Benzpyrene
D001665	Binding Sites	The parts of a macromolecule that directly participate in its specific combination with another molecule.	Combining Site,Binding Site,Combining Sites,Site, Binding,Site, Combining,Sites, Binding,Sites, Combining
D013050	Spectrometry, Fluorescence	Measurement of the intensity and quality of fluorescence.	Fluorescence Spectrophotometry,Fluorescence Spectroscopy,Spectrofluorometry,Fluorescence Spectrometry,Spectrophotometry, Fluorescence,Spectroscopy, Fluorescence