The Sethyl
analog of methionine. It is a carcinogen and hepatotoxic
agent once proposed as an antineoplastic agent. It inhibits the
incorporation of methionine and glycine into proteins and substitutes
for methionine in transmethylation reactions, the ethyl
group appearing in the products in place of the methyl groups
of methionine (e.g., ethylcholine is formed instead of choline).
Ethionine is currently used only as an experimental compound
in studies of hepatotoxicity and methionine metabolism and
nutrition.