[Kinetic characteristics of DNA alkylation with some chloroethylmethylarylamines and elimination of alkylated bases from DNA].

Kinetics of DNA alkylation with 2',3'-o-[N-2-chloroethyl-N-methylamino)benzylidene]uridine (UCHRCL), uridine-5'-methylphosphate (MepUCHRCL) and 4-(N-2-chloroethyl-N-methylamino)benzylamine (NH2CH2RCl) and kinetics of elimination of alkylated bases have been studied. Efficiency of DNA alkylation (p/s-ratio of rate constant of alkylation to the sum of rate constants of by-reactions of an active intermediate formed from the reagent) increases with an increase of the positive charge of the reagents as well as efficiency of tRNA alkylation. Alkylated bases are eliminated from DNA; rate of elimination depends on the structure of the reagent; it decreases in the series NH2CH2R- greater than greater than UCHR-greater than MepUCHR-. Bases alkylated by NH2CH2RCl and UCHRCl are eliminated from DNA during alkylation; therefore plots of DNA alkylation by NH2CH2RCl have a maximum. DNA alkylated by MepUCHRCl is rather stable; alkylated bases are not eliminated during alkylation. Effect of temperature and pH on elimination has been studied.