Table 1. Kinetic Parameters for Phosphoryl Transfer from 1 mM ATP to Different Phosphoryl Acceptors, Determined at pH 7.5 and 25 °C in 25 mM TEA Buffer and I = 0.15 (NaCl).

enzyme	phosphoryl acceptor	kcat (s–1)a	Km (M)a	kcat/Km (M–1s–1)
RAdK	AMPb	100 ± 2	(8.6 ± 0.6) × 10–5	1.2 × 106
HAdK1	AMPc	475	6.8 × 10–5	7.0 × 106
	2′-dAMPd	92	(1.05 ± 0.06) × 10–3	8.8 × 104
	HPc	no reaction detected		≤1.0 × 10–4
	R5Pe	not saturated		0.014 ± 0.01

^aThe uncertainty in the kinetic parameters is the standard error from the nonlinear least-squares fits of the kinetic data to the Michaelis–Menten equation.

^bDetermined from data reported in Figure S1.

^cPublished data.²³

^dDetermined for data reported in Figure S2.

^eDetermined for data reported in Figure 1.