Pyruvate decarboxylase
| Pyruvate decarboxylase | |||||||||
|---|---|---|---|---|---|---|---|---|---|
Reaction catalyzed by pyruvate decarboxylase:
pyruvate + thiamine pyrophosphate (TPP) → hydroxyethyl-TPP + CO2 |
|||||||||
| Identifiers | |||||||||
| EC number | 4.1.1.1 | ||||||||
| CAS number | 9001-04-1 | ||||||||
| 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 / EGO | ||||||||
|
|||||||||
| Search | |
|---|---|
| PMC | articles |
| PubMed | articles |
| NCBI | proteins |
Pyruvate decarboxylase is a homotetrameric enzyme (EC 4.1.1.1) that catalyses the decarboxylation of pyruvic acid to acetaldehyde and carbon dioxide in the cytoplasm of prokaryotes, and in the cytoplasm and mitochondria of eukaryotes. It is also called 2-oxo-acid carboxylase, alpha-ketoacid carboxylase, and pyruvic decarboxylase. In anaerobic conditions, this enzyme is part of the fermentation process that occurs in yeast, especially of the Saccharomyces genus, to produce ethanol by fermentation. It is also present in some species of fish (including goldfish and carp) where it permits the fish to perform ethanol fermentation (along with lactic acid fermentation) when oxygen is scarce. Pyruvate decarboxylase starts this process by converting pyruvate into acetaldehyde and carbon dioxide. Pyruvate decarboxylase depends on cofactors thiamine pyrophosphate (TPP) and magnesium. This enzyme should not be mistaken for the unrelated enzyme pyruvate dehydrogenase, an oxidoreductase (EC 1.2.4.1), that catalyzes the oxidative decarboxylation of pyruvate to acetyl-CoA.
Pyruvate decarboxylase occurs as a dimer of dimers with two active sites shared between the monomers of each dimer. The enzyme contains a beta-alpha-beta structure, yielding parallel beta-sheets. It contains 563 residue subunits in each dimer; the enzyme has strong intermonomer attractions, but the dimers loosely interact to form a loose tetramer.
This enzyme is a homotetramer, and therefore has four active sites. The active sites are inside a cavity in the core of the enzyme where hydrogen bonding can occur and where the pyruvate reacts with TPP. Each active site has 20 amino acids, including the acidic Glu-477 (contributes to the stability of the TPP ring) and Glu-51 (aids in cofactor binding). These Glutamates also contribute to forming the TPP ylid, acting as proton donators to the TPP aminopyrimidine ring. The microenvironment around this Glu 477 is very nonpolar, contributing to a higher than normal pKa (normal Glu and Asp pKa's are around 4.6 in small proteins).
...
Wikipedia