TABLE 3

Enzyme inhibition study of recombinant human UMP/CMP kinase: inhibition of CMP phosphorylation by dCMP

The enzyme inhibition studies were performed with 0 to 80 μM of CMP in the presence of different concentrations of dCMP. Reactions were performed with ATP/Mg concentrations either 0.1/2 or 2/2 mM, 2 mM DTT, and 10 mM NaF. The Ki values of dCMP for inhibiting CMP phosphorylation (KidCMP on CMPK) were derived according to Fig. 4. The data are presented as mean with S.D. from at least three separate experiments. The Km values of dCMP, as a reference to compare with Ki values, are from Table 1.

ATP/Mg KmdCMPKi on CMPK
μM
0.1/2 mM 406 ± 23 440 ± 70
2/2 mM 906 ± 36 801 ± 128