Protein Domain : Pyrophosphate-energised proton pump IPR004131

Type	Family
Description	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 [ ]. The latter type is represented by this group of proteins. H+-PPases () are also called vacuolar-type inorganic pyrophosphatases (V-PPase) or pyrophosphate-energised vacuolar membrane proton pumps [ ]. In plants, vacuoles contain two enzymes for acidifying the interior of the vacuole, the V-ATPase and the V-PPase (V is for vacuolar) []. In Arabidopsis, AVP1 contributes to H+-electrochemical potential difference between the citosol and vacuole lumen and also facilitates auxin transport by modulating apoplastic pH and regulates auxin-mediated developmental processes [].Two distinct biochemical subclasses of H+-PPases have been characterised to date: K+-stimulated and K+-insensitive [ ].
Short Name	PPase-energised_H-pump