TABLE 2.

Affinity measurements for CNB-A, CNB-B, and mutants

K_D is the equilibrium constant for association. EC₅₀ is the half-maximal effective concentration.

PKGII(CNB-B)	8-Fluo-cGMPa	cGMPb	cAMPb
Wild type	23.5 ± 0.03 nm	31 ± 1 nm	15 ± 1 μm
Q335A	31 ± 1 nm	90 ± 4 nm	25 ± 3 μm
D411A	1.8 ± 0.2 nm	262 ± 5 nm	23.4 ± 4 μm
D412A	17 ± 0.4 nm	1065 ± 39 nm	13.2 ± 1 μm
R415A	47 ± 1 nm	964 ± 101 nm	25 ± 1 μm
PKGII(CNB-A)
Wild type	44 ± 1 nmc	43.8 ± 1 nm	418 ± 19 nm

^a K_D ± S.E. direct measurements. FP measurements were at least in triplicate (n = 3).

^b EC₅₀ ± S.E.^a competition experiments. FP measurements were at least in triplicate (n = 3).

^c This value is for 8-Fluo-cAMP rather than for 8-Fluo-cGMP.