Kinetic properties and stereospecificity of the monomeric dUTPase from herpes simplex virus type 1

Kinetic properties of the monomeric enzyme dUTPase from herpes simplex virus type 1 (HSV) were investigated and compared to those previously determined for homotrimeric dUTPases of bacterial and retroviral origins. The HSV and Escherichia coli dUTPases are equally potent as catalysts towards the native substrate dUTP with a k(cat)/K-M of about 10(7) M-1 s(-1) and a K-M of 0.3 mu M. However, the viral enzymes are less specific than the bacterial enzyme, The HSV and E. coli dUTPases show the same stereospecificity towards the racemic substrate analogue dUTP alpha S (2'-deoxyuridine 5'-(alpha-thio)triphosphate), suggesting that they have identical reaction mechanisms. (C) 1998 Federation of European Biochemical Societies.