Phosphoenolpyruvate carboxylase (IPR021135)

Short name: PEP_COase

Overlapping homologous superfamilies

Family relationships


Phosphoenolpyruvate carboxylase (PEPCase), an enzyme found in all multicellular plants, catalyses the formation of oxaloacetate from phosphoenolpyruvate (PEP) and a hydrocarbonate ion [PMID: 1450389]. This reaction is harnessed by C4 plants to capture and concentrate carbon dioxide into the photosynthetic bundle sheath cells. It also plays a key role in the nitrogen fixation pathway in legume root nodules: here it functions in concert with glutamine, glutamate and asparagine synthetases and aspartate amido transferase, to synthesise aspartate and asparagine, the major nitrogen transport compounds in various amine-transporting plant species [PMID: 1421147].

PEPCase also plays an antipleurotic role in bacteria and plant cells, supplying oxaloacetate to the TCA cycle, which requires continuous input of C4 molecules in order to replenish the intermediates removed for amino acid biosynthesis [PMID: 2779518]. The C terminus of the enzyme contains the active site that includes a conserved lysine residue, involved in substrate binding, and other conserved residues important for the catalytic mechanism [PMID: 1508152].

Based on sequence similarity, PEPCase enzymes can be grouped into two distinct families, one found primarily in bacteria and plants, and another found primarily in archaea.

GO terms

Biological Process

GO:0015977 carbon fixation
GO:0006099 tricarboxylic acid cycle

Molecular Function

GO:0008964 phosphoenolpyruvate carboxylase activity

Cellular Component

No terms assigned in this category.

Contributing signatures

Signatures from InterPro member databases are used to construct an entry.