The direct-acting carcinogens acetoxyacetylaminofluorene, methylnitrosourea, and N-methyl-N'-nitro-N-nitrosoguanidine were tested for their ability to inhibit rat liver DNA polymerase-alpha, -beta, and -gamma activity in vitro. DNA polymerase-alpha was the most sensitive, polymerase-beta was the most resistant, and polymerase-gamma exhibited an intermediate response. When the reactions were reassayed in the presence and absence of dithiothreitol, a thiol reducing agent, it was shown that the inhibition by carcinogens was generally reversible with increasing dithiothreitol, except that polymerase-beta recovered only 80-90% of control values. These and binding data suggest that DNA polymerase-beta, the putative repair enzyme, is highly resistant to carcinogen damage. This resistance may contribute to the retention of normal function and fidelity of the repair enzyme during carcinogen exposure in vivo and to a normal cellular repair.
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March 1981
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Research Article|
March 01 1981
Differential inhibition of rat liver DNA polymerases in vitro by direct-acting carcinogens and the protective effect of a thiol reducing agent
Publisher: Portland Press Ltd
Online ISSN: 1470-8728
Print ISSN: 0264-6021
© 1981 London: The Biochemical Society
1981
Biochem J (1981) 193 (3): 985–990.
Citation
J Y Chan, F F Becker; Differential inhibition of rat liver DNA polymerases in vitro by direct-acting carcinogens and the protective effect of a thiol reducing agent. Biochem J 1 March 1981; 193 (3): 985–990. doi: https://doi.org/10.1042/bj1930985
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