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Mutagen activation by cDNA‐expressed P 1 450, P 3 450, and P450a
Author(s) -
Aoyama Toshifumi,
Gonzalez Frank J.,
Gelboin Harry V.
Publication year - 1989
Publication title -
molecular carcinogenesis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.254
H-Index - 97
eISSN - 1098-2744
pISSN - 0899-1987
DOI - 10.1002/mc.2940010408
Subject(s) - mutagen , biology , complementary dna , carcinogen , rna , enzyme , microbiology and biotechnology , t7 rna polymerase , biochemistry , escherichia coli , gene , bacteriophage
cDNAs for rodent P 1 450, P 3 450, and P450a were expressed in the modified vaccinia virus‐T7 RNA polymerase system. Each P450 exhibited its appropriate molecular weight and characteristic enzyme activity. Aryl hydrocarbon hydroxylase activity was catalyzed by P 1 450, acetanilide hydroxylase by P 3 450, and testosterone 7a‐hydroxylase by P450a. Ethoxycoumarin deethylase was exhibited by both P 1 450 and P3450. Each expressed P450 was also analyzed for its ability to activate 19 carcinogens of diverse classes to their mutagenic forms. Most notable was the activation of several polycyclic aromatic hydrocarbons by P 1 and the activation of acetylaminofluorene, 4‐aminobiphenyl, and several heterocyclic amine food pyrolysate products by P 3 450. P450a, in contrast, showed slight mutagen activation only toward N ‐hydroxy‐2‐acetyl aminofluorene. The vaccinia virus‐T7 RNA polymerase system described here can express cDNAs for diverse forms of P450, each of which can then be characterized for substrate and product specificity and for mutagen activation.