This enzyme belongs to the family of hydrolases, specifically those acting on acid anhydrides in phosphorus-containing anhydrides. The systematic name of this enzyme class is 1-(5-phosphoribosyl)-ATP diphosphohydrolase. Other names in common use include phosphoribosyl-ATP pyrophosphatase, and phosphoribosyladenosine triphosphate pyrophosphatase. This enzyme participates in histidine metabolism. It employs one cofactor, H+.