fumarate

Fumarate refers to the dianion of fumaric acid and to salts containing that ion. It most commonly denotes the trans isomer of but-2-enedioic acid (trans- fumaric acid) and its salts, as opposed to the cis isomer known as maleate.

Chemically, fumarate is an unsaturated dicarboxylate with a rigid, planar structure due to the trans double bond between the central carbons. The neutral acid is fumaric acid (C4H4O4); the commonly encountered species in solution are the fumarate ion (C4H2O4 2−) and its salts, such as disodium fumarate or potassium fumarate.

Biologically, fumarate is a key intermediate in cellular metabolism. In the citric acid cycle, fumarate is formed from succinate by succinate dehydrogenase and is then hydrated by fumarase to malate, which proceeds to oxaloacetate. Fumarate also appears in plants and microorganisms as part of various metabolic pathways, and it can participate in biochemical reactions that modify cellular proteins under certain conditions.

Applications and occurrence: Fumarate salts are used as food additives and acidity regulators (for example, E297) and as reagents in organic synthesis. Dimethyl fumarate, an ester derivative, is used as a pharmaceutical agent and is approved for some indications in multiple regions (notably for certain autoimmune diseases). Fumarates also serve as crosslinking agents in polymer chemistry in some industrial contexts.

Safety and notes: Fumarate-containing compounds are typically handled under standard chemical safety practices. Ingestion of large amounts or exposure to vapors can cause irritation; certain metabolic disorders involving fumarate intermediates can have clinical implications.