Design and synthesis of inhibitors of adenosine and AMP deaminases.

Nucleosides and nucleotides which are able to undergo covalent hydration in the aglycone ring system are potential inhibitors of the enzymes adenosine deaminase (ADA) and AMP deaminase, respectively. Calculations of the enthalpy of covalent hydration and of enzyme binding energy have been used to design new inhibitors of ADA. The ribosyl triazolotriazine 16, which was synthesized as a result of these calculations, exists predominantly as the covalent hydrate 18 in water and is a potent inhibitor of mammalian ADA (IC(50) 50 nM).