Carboxylated

Carboxylated refers to a molecule that has been modified to bear one or more carboxyl groups (-COOH or its conjugate base -COO-). In chemistry, carboxylation is the process of introducing a carboxyl group into an organic substrate, typically by reaction with carbon dioxide (CO2) or by oxidation of a carbon center followed by carboxylation. The term can describe neutral carboxylic acids, their salts, or their esters formed after modification.

Common examples include carboxylated polymers such as carboxymethyl cellulose (CMC), where carboxymethyl groups are introduced onto cellulose to impart water solubility and thickening properties. Carboxylated surfaces and polymers are also used in chromatography and catalysis. In organic synthesis, carboxylation of organometallic reagents with CO2 affords carboxylic acids after workup; electrophilic and catalytic methods enable broader substrate scope, including hydroxy- and amino-carboxylation.

Biology features a specific form known as gamma-carboxylation, an enzymatic modification in which glutamate residues are converted to gamma-carboxyglutamate by vitamin K–dependent carboxylases. This modification enables calcium binding and is essential for the activity of several blood coagulation factors and bone proteins.

Chemically, carboxylated species are typically more polar and acidic than their precursors. They may exist as carboxylic acids, carboxylate salts, or esters, and the nature of substitution influences solubility, reactivity, and metal-binding propensity. Carboxylation is a common strategy to increase functionality or introduce negative charge for binding, solubility, or crosslinking.