Fig. 3.

Dilution-jump kinetic experiments for dUTP hydrolysis. High concentrations of SAMHD1 and various nucleotide combinations were incubated as indicated in pre- and postjump reactions. (A) SAMHD1 was incubated with GTP (0.5 mM) and dUTP (5 mM), GTP alone (0.5 mM), dUTP alone (5 mM), or no nucleotide before dilution. (B) Inclusion of 0.5 mM GTP in the postjump reaction did not enhance the postjump kinetics. For comparison, the dashed line shows the curve from the dUTP-only postjump condition in A. (C) Time dependence of prejump reactions containing only dGTP (5 mM).