Specific positions involved in enzyme catalyzed covalent binding of benzo(a)pyrene to poly(G)

Journal Article · Thu Apr 01 00:00:00 EST 1976 · Proc. Natl. Acad. Sci. U.S.A.; (United States)

DOI:https://doi.org/10.1073/pnas.73.4.1117· OSTI ID:7185346

Meehan, T; Warshawsky, D; Calvin, M

Covalent binding of benzo(a)pyrene to poly(G) was studied with the use of a radioactive assay and specifically labeled substrates to define the role of the 1,3- and 6-positions of the hydrocarbon during this process. Binding was shown to be dependent on microsomes, NADPH, O/sub 2/ and poly(G). 7,8-Benzoflavone and 2',2'-diethylaminoethyl-2,2-diphenyl valerate were inhibitory whereas modulators of epoxide hydrase activity had little effect. /sup 3/H and /sup 14/C studies suggested a possible loss of one to two protons. Incorporation of (6-/sup 3/H/sub 1/)benzo(a)pyrene provided evidence that the 6-position of the hydrocarbon was not metabolized during covalent attachment to poly(G) and, furthermore, results with (1,3,6-/sup 3/H)benzo(a)pyrene suggest that the 1- and 3-positions may not be involved either. After scaling up of the standard assay 20-fold, characterization of the tritiated BaP-poly(G) complex was carried out by hydrolysis and subsequent chromatography. Thin-layer chromatography of the isolated hydrolysis products treated with HCl or alkaline phosphatase indicated that the complex formed between BaP and poly(G) was covalently linked and composed of hydrocarbon-nucleotide(s).

• Research Organization: Univ. of California, Berkeley
• OSTI ID: 7185346
• Journal Information: Proc. Natl. Acad. Sci. U.S.A.; (United States), Journal Name: Proc. Natl. Acad. Sci. U.S.A.; (United States) Vol. 73:4; ISSN PNASA
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
38 RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEAR CHEMISTRY
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AROMATICS
BENZOPYRENE
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BIOCHEMICAL REACTION KINETICS
CARBON 14
CARBON ISOTOPES
CARCINOGENS
CATALYSIS
CELL CONSTITUENTS
CHEMICAL REACTIONS
CHROMATOGRAPHY
COENZYMES
COMPLEXES
CONDENSED AROMATICS
COVALENCE
CRYOGENIC FLUIDS
DECOMPOSITION
ELEMENTS
ENZYMES
EVEN-EVEN NUCLEI
FLUIDS
HYDROCARBONS
HYDROGEN ISOTOPES
HYDROLYSIS
ISOTOPES
KINETICS
LABELLING
LIGHT NUCLEI
LYSIS
METABOLISM
MICROSOMES
NAD
NONMETALS
NUCLEI
NUCLEOTIDES
ODD-EVEN NUCLEI
ORGANIC COMPOUNDS
ORGANOIDS
OXYGEN
RADIOISOTOPES
REACTION KINETICS
SEPARATION PROCESSES
SOLVOLYSIS
THIN-LAYER CHROMATOGRAPHY
TRITIUM
YEARS LIVING RADIOISOTOPES