Interactions of Calf Spleen Purine Nucleoside Phosphorylase with Antiviral Acyclic Nucleoside Phosphonate Inhibitors: Kinetics and Emission Studies

Abstract

Association between calf spleen purine nucleoside phosphorylase and a series of phosphonylalkoxyalkyl derivatives of purine bases was studied by inhibition kinetics and fluorimetric titrations. Dissociation constants, determined by fluorimetric titration in phosphate-free conditions, were lower than inhibition constants in 1 mM phosphate, and inhibition was still weaker in 50 mM phosphate, in accord with the postulated bisubstrate analogue character of this class of inhibitors.