Metabolism and covalent binding of vic-dihaloalkanes, vinyl halides and acrylonitrile.

The roles of various metabolic pathways in DNA and protein alkylation are discussed here. Simple vinyl halides are oxidized to 2-haloethylene oxides and 2-haloacetaldehydes, which alkylate DNA and proteins, respectively. Polysubstituted vinyl halides are oxidized with group transfer to yield halocarbonyl compounds which alkylate proteins. Oxidation of vic-dihaloalkanes results in protein alkylation while glutathione conjugates alkylate DNA. Acrylonitrile, without previous activation, alkylates proteins and glutathione. Oxidation of acrylonitrile yields a relatively stable epoxide which can react with DNA in vitro, but alkylation by this epoxide does not occur readily in vivo. Hard-soft acid-base theory is of some use in understanding why some adducts are formed in preference to others.