1-Aminocyclopropane-1-carboxylic acid (ACC) is a disubstituted cyclic alpha-amino acid

Amino acid

Amino acids are molecules containing an amine group, a carboxylic acid group and a side-chain that varies between different amino acids. The key elements of an amino acid are carbon, hydrogen, oxygen, and nitrogen...

 in which a three-membered cyclopropane

Cyclopropane

Cyclopropane is a cycloalkane molecule with the molecular formula C3H6, consisting of three carbon atoms linked to each other to form a ring, with each carbon atom bearing two hydrogen atoms...

 ring is fuzed to the C(alpha)-atom of the amino acid.

ACC plays an important role in the biosynthesis of the plant hormone

Hormone

A hormone is a chemical released by a cell or a gland in one part of the body that sends out messages that affect cells in other parts of the organism. Only a small amount of hormone is required to alter cell metabolism. In essence, it is a chemical messenger that transports a signal from one...

 ethylene

Ethylene

Ethylene is a gaseous organic compound with the formula . It is the simplest alkene . Because it contains a carbon-carbon double bond, ethylene is classified as an unsaturated hydrocarbon. Ethylene is widely used in industry and is also a plant hormone...

. It is synthesized by the enzyme ACC synthase from methionine

Methionine

Methionine is an α-amino acid with the chemical formula HO2CCHCH2CH2SCH3. This essential amino acid is classified as nonpolar. This amino-acid is coded by the codon AUG, also known as the initiation codon, since it indicates mRNA's coding region where translation into protein...

 and converted to ethylene by ACC oxidase .

ACC is also a non-physiological partial agonist

Partial agonist

Partial agonists bind and activate a given receptor, but have only partial efficacy at the receptor relative to a full agonist...

 of the mammalian NMDA receptor

NMDA receptor

The NMDA receptor , a glutamate receptor, is the predominant molecular device for controlling synaptic plasticity and memory function....

.