Biology:Proton-pumping pyrophosphatase
| Inorganic H+ pyrophosphatase | |||||||||
|---|---|---|---|---|---|---|---|---|---|
| Identifiers | |||||||||
| Symbol | H_PPase | ||||||||
| Pfam | PF03030 | ||||||||
| InterPro | IPR004131 | ||||||||
| TCDB | 3.A.10 | ||||||||
| OPM superfamily | 390 | ||||||||
| OPM protein | 4a01 | ||||||||
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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
- ↑ 1.0 1.1 "Functional complementation of yeast cytosolic pyrophosphatase by bacterial and plant H+-translocating pyrophosphatases". Proc. Natl. Acad. Sci. U.S.A. 99 (25): 15914–9. December 2002. doi:10.1073/pnas.242625399. PMID 12451180.
- ↑ 2.0 2.1 "H+ -PPases: a tightly membrane-bound family". FEBS Lett. 457 (3): 527–33. September 1999. doi:10.1016/S0014-5793(99)90617-8. PMID 10523139.
- ↑ 3.0 3.1 "A thermostable K(+)-stimulated vacuolar-type pyrophosphatase from the hyperthermophilic bacterium Thermotoga maritima". FEBS Lett. 496 (1): 6–11. May 2001. doi:10.1016/S0014-5793(01)02390-0. PMID 11343697.
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