Carboxylesterase
| carboxylesterase | |||||||||
|---|---|---|---|---|---|---|---|---|---|
| Identifiers | |||||||||
| EC no. | 3.1.1.1 | ||||||||
| CAS no. | 9016-18-6 | ||||||||
| Databases | |||||||||
| IntEnz | IntEnz view | ||||||||
| BRENDA | BRENDA entry | ||||||||
| ExPASy | NiceZyme view | ||||||||
| KEGG | KEGG entry | ||||||||
| MetaCyc | metabolic pathway | ||||||||
| PRIAM | profile | ||||||||
| PDB structures | RCSB PDB PDBe PDBsum | ||||||||
| Gene Ontology | AmiGO / QuickGO | ||||||||
| |||||||||
The enzyme carboxylesterase (or carboxylic-ester hydrolase, EC 3.1.1.1; systematic name carboxylic-ester hydrolase) catalyzes reactions of the following form:
- a carboxylic ester + H2O an alcohol + a carboxylate
Most enzymes from this group are serine hydrolases belonging to the superfamily of proteins with α/β hydrolase fold. Some exceptions include an esterase with β-lactamase-like structure (PDB: 1ci8).
Carboxylesterases are widely distributed in nature, and are common in mammalian liver. Many participate in phase I metabolism of xenobiotics such as toxins or drugs; the resulting carboxylates are then conjugated by other enzymes to increase solubility and eventually excreted. The essential polyunsaturated fatty acid arachidonic acid (AA C20H32O2; 20:4, n-6), formed by the synthesis from dietary linoleic acid (LA: C18H32O2 18:2, n-6), has a role as a human carboxylesterase inhibitor.
The carboxylesterase family of evolutionarily related proteins (those with clear sequence homology to each other) includes a number of proteins with different substrate specificities, such as acetylcholinesterases.