Malonate

The malonate or propanedioate ion is CH2(COO)22&minus; (malonic acid minus two hydrogen ions). Malonate compounds include salts and esters of malonic acid, such as
 * diethyl malonate, (C2H5)2(C3H2O4),
 * dimethyl malonate, (CH3)2(C3H2O4),
 * disodium malonate, Na2(C3H2O4).

Malonate is a competitive inhibitor of the enzyme succinate dehydrogenase: malonate binds to the active site of the enzyme without reacting, and so competes with succinate, the usual substrate of the enzyme. The observation that malonate is a competitive inhibitor of succinate dehydrogenase was used to deduce the structure of the active site in that enzyme.