TABLE 1.

Steady-state parameters for dCK reactions^a

Substrate	Km (μM)	kcat (s−1)	kcat/Km (μM−1 s−1)	Relative substrate specificity
2′-Deoxycytidine	0.4 ± 0.1	0.025	6.3 × 10−2	1
Gemcitabine	1.4 ± 0.2	0.038	2.7 × 10−2	0.43
2′-FdC	4.7 ± 1.2	0.050	1.1 × 10−2	0.17
2′-C-Me-dC	46.2 ± 10.7	0.048	1.0 × 10−3	0.016
Cytidine	6.6 ± 1.0	0.009	1.4 × 10−3	0.022
PSI-6130	81.2 ± 8.0	0.016	1.9 × 10−4	0.003
2′-C-Me-C	914 ± 209	0.011	1.2 × 10−5	0.0002

^aValues are reported as means ± standard deviations.