Kinetics, inhibition and oligomerization of Epstein-Barr virus protease

Epstein-Barr virus (EBV) is an omnipresent human virus causing infectious mononucleosis and EBV associated cancers. Its protease is a possible target for antiviral therapy. We studied its dimerization and enzyme kinetics with two enzyme assays based either on the release of paranitroaniline or 7-amino-4-methylcoumarin from labeled pentapeptide (Ac-KLVQA) substrates. The protease is in a monomer–dimer equilibrium where only dimers are active. In absence of citrate the Kd is 20 μM and drops to 0.2 μM in presence of 0.5 M citrate. Citrate increases additionally the activity of the catalytic sites. The inhibitory constants of different substrate derived peptides and α-keto-amide based inhibitors, which have at best a Ki of 4 μM, have also been evaluated.