Regulation and activity of cytosolic 5′-nucleotidase II: A bifunctional allosteric enzyme of the Haloacid Dehalogenase superfamily involved in cellular metabolism

In many vertebrate tissues, cytosolic 5′-nucleotidase II (cN-II) either hydrolyses or phosphorylates a number of purine (monophosphorylated) nucleosides through a scheme common to the Haloacid Dehalogenase superfamily members. It possesses a pivotal role in purine cellular metabolism and it acts on antitumoural and antiviral nucleoside analogues, thus being of potential therapeutic importance. cN-II is Mg2+-dependant, regulated and stabilised by several factors such as allosteric effectors ATP and 2,3-DPG, although these are not directly involved in the reaction stoichiometry. We review herein the experimental knowledge currently available about this remarkable enzymatic activity.