decarboxylates

Decarboxylation is the chemical reaction in which a carboxyl group is removed from an organic molecule as carbon dioxide. It occurs in both organic synthesis and biological metabolism, often altering the structure and reactivity of the substrate.

In organic chemistry, decarboxylation can proceed through heating or catalysis and is a common step in various synthetic sequences. Beta-keto acids decarboxylate readily to yield ketones, and malonic esters can lose CO2 under basic conditions to furnish substituted products. Decarboxylation is also exploited in decarboxylative coupling reactions and other transformations that form carbon–carbon bonds or restructure molecular frameworks.

In biochemistry, decarboxylation is typically catalyzed by enzymes known as decarboxylases. These enzymes remove CO2 from substrates such as amino acids to generate amines, a process important in neurotransmitter and hormone biosynthesis. Examples include glutamate decarboxylase, which converts glutamate to GABA, and various aromatic amino acid decarboxylases that produce biogenic amines. Many cellular decarboxylations are oxidative, meaning they are coupled with oxidation and involve coenzymes or electron transfer partners. Prominent oxidative decarboxylations include the conversion of pyruvate to acetyl-CoA by the pyruvate dehydrogenase complex and the decarboxylations of isocitrate and alpha-ketoglutarate within the citric acid cycle.

The release of carbon dioxide during decarboxylation has implications for energy metabolism, carbon flux, and atmospheric CO2. The concept underpins both practical synthetic strategies in chemistry and fundamental pathways in biology.

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