Ecto-Nucleoside Triphosphate Diphosphohydrolase Activities in Trypanosomatids:Possible Roles in Infection, Virulence and Purine Recycling

Ecto-nucleoside triphosphate diphosphohydrolases (ecto-NTPDases), also known as ecto-ATPases and/or ecto- apyrases, are integral membrane glycoproteins or soluble enzymes that are dependent on divalent cations. These ecto- enzymes are important ecto-nucleotidases that are characterized by the ability to hydrolyze nucleoside triphosphates and nucleoside diphosphates to the monophosphate form. The hydrolysis of nucleoside monophosphates to nucleosides such as adenosine may then be catalyzed by the action of ecto-5´nucleotidases. The present study reviews the sequential hy- drolysis of ATPADPAMPadenosine catalyzed by these ecto-enzymes from different trypanosomatids. These reactions participate in the salvage of purines in these parasites and simultaneously interfere with the establishment of in- fection and changes in the host immune response.