1-Aminocyclopropane-1-carboxylic acid

1-Aminocyclopropane-1-carboxylic acid (ACC) is a disubstituted cyclic alpha-amino acid that plays a crucial role in the biosynthesis of the plant hormone ethylene. It is a derivative of the amino acid methionine and is synthesized by the enzyme ACC synthase (ACS) in the Yang cycle. ACC is then converted to ethylene by the enzyme ACC oxidase (ACO).

Structure and properties

ACC is a cyclic amino acid with a three-membered ring, known as a cyclopropane ring. The molecule has two functional groups, an amino group (-NH2) and a carboxylic acid group (-COOH), which are both attached to the same carbon atom in the ring, hence the name 1-Aminocyclopropane-1-carboxylic acid. The presence of these functional groups gives ACC both basic and acidic properties.

Role in ethylene biosynthesis

In plants, ACC is a key intermediate in the biosynthesis of ethylene, a hormone that regulates various aspects of plant growth and development, including fruit ripening, flower wilting, and leaf fall. The conversion of ACC to ethylene is catalyzed by the enzyme ACC oxidase, a process that requires oxygen and produces carbon dioxide as a byproduct.

ACC synthase and ACC oxidase

ACC synthase and ACC oxidase are the two key enzymes involved in ethylene biosynthesis. ACC synthase catalyzes the conversion of S-adenosyl-L-methionine (SAM) to ACC, while ACC oxidase catalyzes the final step in the pathway, converting ACC to ethylene.

Applications in agriculture

Due to its role in ethylene biosynthesis, ACC has been studied for its potential applications in agriculture. For example, it has been used to induce fruit ripening in a controlled manner, and to delay leaf senescence in cut flowers. In addition, inhibitors of ACC synthase and ACC oxidase have been developed to control the ripening and senescence processes in crops and ornamental plants.

See also

• Ethylene
• ACC synthase
• ACC oxidase
• S-adenosyl-L-methionine
• Yang cycle

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