Succinic acid (IUPAC systematic name: butanedioic acid; historically known as spirit of amber) is a dicarboxylic acid. Succinate plays a biochemical role in the citric acid cycle.
At room temperature
, pure succinic acid is a solid
that forms colorless, odorless crystals
. It has a melting point
of 185 °C and a boiling point
of 235 °C. It is a diprotic
acid. The carboxylate anion
is called succinate
of succinic acid are called alkyl succinates
Succinate is a component of the citric acid cycle
and is capable of donating electrons
to the electron transfer chain
via the following reaction:
- succinate + FAD → fumarate + FADH2
This is catalysed by the enzyme succinate dehydrogenase (or complex II of the mitochondrial ETC). The complex is a 4 subunit membrane-bound lipoprotein which couples the oxidation of succinate to the reduction of ubiquinone. Intermediate electron carriers are FAD and three Fe2S2 clusters part of subunit B.
Spirit of amber was procured from amber
by pulverising and distilling it using a sand bath
. It was chiefly used externally for rheumatic
aches and pains, and internally in inveterate gleets
The acid is combustible
, capable of causing burns. "Harmful by inhalation, ingestion and through skin absorption. Wash after handling. Eye contact may cause serious damage."
In nutraceutical form as a food additive and dietary supplement, is safe and approved by the FDA.
Succinic acid can be converted to fumaric acid
by oxidation. The diethyl ester is a substrate in the Stobbe condensation
Succinic acid is created as a byproduct of the fermentation of sugar. It lends to fermented beverages such as wine and beer a common taste that is a combination of saltiness, bitterness and acidity.