View source for Apyrase

{{Short description|Enzyme}}
{{Infobox protein family
| Symbol = Apyrase
| Name = Apyrase
| image = PDB 1s18 EBI.jpg
| width = 
| caption = structure and protein design of human apyrase
| Pfam = PF06079
| Pfam_clan =  
| InterPro = IPR009283
| SMART = 
| PROSITE = 
| MEROPS = 
| SCOP = 1s1d
| TCDB = 
| OPM family = 
| OPM protein = 
| CAZy = 
| CDD = 
|Membranome superfamily = 581
}}
'''Apyrase''' ({{EC number|3.6.1.5}}, ''ATP-diphosphatase'', [[adenosine]] diphosphatase, ''ADPase'', ''ATP diphosphohydrolase'') is a [[calcium]]-activated plasma membrane-bound [[enzyme]] (magnesium can also activate it) ({{EC number|3.6.1.5}}) that [[catalyst|catalyses]] the [[hydrolysis]] of [[Adenosine triphosphate|ATP]] to yield [[Adenosine monophosphate|AMP]] and [[inorganic phosphate]]. Two isoenzymes are found in commercial preparations from ''S. tuberosum''. One with a higher ratio of substrate selectivity for ATP:ADP (approx 10) and another with no selectivity (ratio 1).

It can also act on [[Adenosine diphosphate|ADP]] and other [[Nucleoside triphosphate|nucleoside triphosphates]] and [[Nucleoside diphosphate|diphosphates]] with the general reaction being NTP -> NDP + Pi -> NMP + 2Pi. This is the same activity that has been employed in the degradation of unincorporated nucleosides during [[pyrosequencing]].

The salivary apyrases of blood-feeding [[arthropod]]s are [[nucleotide]] hydrolysing [[enzyme]]s that are implicated in the inhibition of host [[platelet aggregation]] through the [[hydrolysis]] of [[extracellular]] [[adenosine diphosphate]].<ref name="pmid12234496">{{cite journal |vauthors=Smith TM, Hicks-Berger CA, Kim S, Kirley TL | title = Cloning, expression, and characterization of a soluble calcium-activated nucleotidase, a human enzyme belonging to a new family of extracellular nucleotidases | journal = Arch. Biochem. Biophys. | volume = 406 | issue = 1 | pages = 105–15 |date=October 2002 | pmid = 12234496 | doi = 10.1016/S0003-9861(02)00420-4}}</ref>

==References==
{{reflist}}

==External links==
* {{MeshName|Apyrase}}
{{InterPro content|IPR009283}}

{{Acid anhydride hydrolases}}
{{Enzymes}}
{{Portal bar|Biology|border=no}}

[[Category:Protein families]]
[[Category:EC 3.6.1]]


{{3.6-enzyme-stub}}