What does carboxylase mean?
A carboxylase is any enzyme that catalyzes a carboxylation reaction — the addition of a carboxyl group (–COOH) to an organic molecule — or the reverse process of decarboxylation, in which carbon dioxide is released. These enzymes are central to metabolism: ribulose bisphosphate carboxylase fixes atmospheric carbon dioxide during photosynthesis, while acetyl-CoA carboxylase regulates fatty acid synthesis and pyruvate carboxylase supports gluconeogenesis. The word belongs firmly to biochemistry, appearing in research papers, textbooks, and clinical discussions rather than everyday conversation. Because many named enzymes end in '-ase', the suffix signals enzymatic function at a glance; the 'carboxyl-' prefix identifies the chemical group involved. For students of biology or medicine, recognizing carboxylase names provides an immediate clue to what a given enzyme does in a metabolic pathway.
nounAn enzyme that catalyzes the addition of a carboxyl group to a substrate, or the removal of carbon dioxide in decarboxylation reactions.
- Any enzyme that catalyzes a carboxylation or decarboxylation reaction.
"Ribulose-1,5-bisphosphate carboxylase is the most abundant enzyme on Earth, fixing carbon dioxide during photosynthesis."
"Pyruvate carboxylase converts pyruvate into oxaloacetate in the first committed step of gluconeogenesis."
"Deficiency of biotin-dependent carboxylases can disrupt fatty acid synthesis and amino acid metabolism."
Regular plural, used when discussing multiple such enzymes collectively.
"Biotin serves as a cofactor for several carboxylases in human metabolism."
The carboxylase RuBisCO is so plentiful that it's widely considered the most abundant protein on the planet.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of carboxylase
The word carboxylase was formed in the late nineteenth century from 'carboxyl', the name for the –COOH group, combined with '-ase', the suffix coined by French chemist Émile Duclaux in 1897 for enzymes. 'Carboxyl' itself derives from 'carbon' (from Latin carbo, meaning coal) plus 'oxygen'. The '-ase' convention spread rapidly across chemistry, so carboxylase shares its suffix with thousands of other enzyme names such as amylase and oxidase.
How carboxylase is actually used
A technical term confined almost entirely to biochemistry and molecular biology; rarely encountered outside scientific literature and textbooks. In speech, specific carboxylases are usually named after their substrate (e.g. 'pyruvate carboxylase').
Easily confused with carboxylase
Carboxyl refers to the chemical group (–COOH) itself, whereas carboxylase is the enzyme that transfers or removes such groups.
To carboxylate means to introduce a carboxyl group into a compound, while a carboxylase is the enzyme that performs this reaction.