TABLE 7.

Steady-state catalytic constants for guanosine prodrug deamination by calf ADA relative to adenosine

Compound	kcat (s−1)	Km (μM)	kcat/Km (μM−1 s−1)
Adenosine	110 ± 7	17 ± 4	6.5
DAPDa	0.2 ± 0.01	11 ± 0.9	0.02
Cyclo-d4G	0.01 ± 0.001	96 ± 27	0.0001
ABC	<1 × 10−4	NDb	NDb

^aData from a previous report (13).

^bND, not determined.