Phylogenetic Tree

Apyrase

This family consists of several eukaryotic apyrase (or adenosine diphosphatase) proteins, and related nucleoside diphosphatases. The salivary apyrases of blood-feeding arthropods are nucleotide hydrolysing enzymes implicated in the inhibition of host platelet aggregation through the hydrolysis of extracellular adenosine diphosphate.

--From Wikipedia