Title: Apyrase
CAS Registry Number: 9000-95-7
Literature References: An enzyme found in plants, especially potatoes. Cofactor: Ca2+. Hydrolyzes acid anhydride links. Substrate: Adenosine triphosphate, adenosine diphosphate (giving adenylate and phosphate). Ref: Krishnan, Arch. Biochem. 20, 272 (1949). Partial purification and properties of potato apyrase: Liebecq et al., Bull. Soc. Chim. Biol. 45, 573 (1963).
Aquaporins Arabinose Arabitol Arachidic Acid Arachidonic Acid

PDB 1s18 EBI.jpg
structure and protein design of human apyrase
Symbol Apyrase
Pfam PF06079
InterPro IPR009283
SCOP 1s1d

Apyrase (EC, ATP-diphosphatase, adenosine diphosphatase, ADPase, ATP diphosphohydrolase) is a calcium-activated plasma membrane-bound enzyme (magnesium can also activate it) (EC that catalyses the hydrolysis of ATP to yield 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 ADP and other nucleoside triphosphates and diphosphates with the general reaction being NTP -> NDP + Pi -> NMP + 2Pi.

The salivary apyrases of blood-feeding arthropods are nucleotide hydrolysing enzymes are implicated in the inhibition of host platelet aggregation through the hydrolysis of extracellular adenosine diphosphate.[1]