The Mechanism of Action of Alkylating Agents.

The term “alkylating agent― has been defined and a detailed discussion made of the mechanisms (Sni and Sn@) by which they interact with nucleophilic centers. The various nucleophiles likely to be encountered in vivo are discussed in terms of their relative reactivities toward alkylating agents. With regard to Sn@ reactors it was possible to group them into four sections on the basis of their chemical reactivity and the “spread― in their affinity toward different nucleophiles. The groups comprised (a) the epoxides, ethyleneimines, and $-lactones; (b) the primary alkyl methanesulfonates; (c) primary alkyl halides; and (d) a-halo acids and ketones. An attempt has been made to correlate the reactivity of the Sn@ and Sni reactors with their known pharmacological properties and the likelihood of their reaction with the various cellular constituents. In particular, the effects of the alkylating agents on nuclear material and cell division, the blood components, male fertility, and the im mune response have been discussed in detail, and the chemistry involved in the inter action of the alkylating agents with compounds of biological importance such as the nucleic acids, proteins, and peptides has been critically examined. The importance and limitations of the alkylating agents as chemothenapeutic drugs and as tools for examining the basic mechanisms involved in carcinogenesis and muta tion have been considered in the light of recent findings.