 |
|
|
|
|
|
|
|
|
|
|
|
| • |
A
variety of chemicals react directly with DNA.
|
|
|
Alkylating
agents are electrophiles that add methyl,
|
|
|
ethyl
and more complicated alkyl groups to nucleic
|
|
|
acid
bases. N-methyl-N'-nitro-N-nitrosoguanidine
|
|
|
(MNNG)
in vivo becomes a highly reactive
|
|
|
methylating
agent. Electrophilic reactants can also be
|
|
generated
by cytochrome P450 oxidation of
|
|
|
xenochemicals.
These chemicals include
|
|
|
benzo[a]pyrene,
acetylaminofluorene and aflatoxin.
|
|
|
Bulky
adducts result. Nitrogen and sulfur mustards
|
|
|
(used in
chemical warfare) link bases on opposite
|
|
|
DNA strands,
creating cross-links.
|
|