Pyrophosphate-energised proton pump (IPR004131)

Short name: PPase-energised_H-pump

Overlapping homologous superfamilies


Family relationships



Two types of proteins that hydrolyse inorganic pyrophosphate (PPi), very different in both amino acid sequence and structure, have been characterised to date: soluble and membrane-bound proton-pumping pyrophosphatases (sPPases and H(+)-PPases, respectively). sPPases are ubiquitous proteins that hydrolyse PPi to release heat, whereas H+-PPases, so far unidentified in animal and fungal cells, couple the energy of PPi hydrolysis to proton movement across biological membranes [PMID: 12451180, PMID: 10523139]. The latter type is represented by this group of proteins. H+-PPases (EC: are also called vacuolar-type inorganic pyrophosphatases (V-PPase) or pyrophosphate-energised vacuolar membrane proton pumps [PMID: 11343697]. In plants, vacuoles contain two enzymes for acidifying the interior of the vacuole, the V-ATPase and the V-PPase (V is for vacuolar) [PMID: 10523139].

Two distinct biochemical subclasses of H+-PPases have been characterised to date: K+-stimulated and K+-insensitive [PMID: 12451180, PMID: 11343697].

GO terms

Biological Process

GO:1902600 proton transmembrane transport

Molecular Function

GO:0009678 hydrogen-translocating pyrophosphatase activity
GO:0004427 inorganic diphosphatase activity

Cellular Component

GO:0016020 membrane

Contributing signatures

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