Proton-pumping pyrophosphatase

Inorganic H+ pyrophosphatase
Identifiers
Symbol H_PPase
Pfam PF03030
InterPro IPR004131
TCDB 3.A.10
OPM superfamily 390
OPM protein 4a01

Two types of inorganic diphosphatase, very different in terms of both amino acid sequence and structure, have been characterised to date: soluble and transmembrane proton-pumping pyrophosphatases (sPPases and H(+)-PPases, respectively). sPPases are ubiquitous proteins that hydrolyse pyrophosphate 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.[1][2] 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.[3] In plants, vacuoles contain two enzymes for acidifying the interior of the vacuole, the V-ATPase and the V-PPase (V is for vacuolar).[2]

Two distinct biochemical subclasses of H+-PPases have been characterised to date: K+-stimulated and K+-insensitive.[1][3]

References

  1. 1 2 Perez-Castineira JR, Lopez-Marques RL, Villalba JM, Losada M, Serrano A (December 2002). "Functional complementation of yeast cytosolic pyrophosphatase by bacterial and plant H+-translocating pyrophosphatases". Proc. Natl. Acad. Sci. U.S.A. 99 (25): 15914–9. doi:10.1073/pnas.242625399. PMC 138539. PMID 12451180.
  2. 1 2 Baltscheffsky M, Schultz A, Baltscheffsky H (September 1999). "H+ -PPases: a tightly membrane-bound family". FEBS Lett. 457 (3): 527–33. doi:10.1016/S0014-5793(99)90617-8. PMID 10523139.
  3. 1 2 Perez-Castineira JR, Lopez-Marques RL, Losada M, Serrano A (May 2001). "A thermostable K(+)-stimulated vacuolar-type pyrophosphatase from the hyperthermophilic bacterium Thermotoga maritima". FEBS Lett. 496 (1): 6–11. doi:10.1016/S0014-5793(01)02390-0. PMID 11343697.
This article incorporates text from the public domain Pfam and InterPro: IPR004131
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