TABLE 4.

Kinetic parameters for phosphodiesterase activity catalyzed by YmdB

Protein and substrate	Mean Km (M) ± SD	Mean Vmax (μmol/min/mg) ± SD	Mean kcat (min−1) ± SD	kcat/Km (min−1 M−1)
WT YmdB
2′,3′-cAMP	(2.0 ±0.2) × 10−4	0.83 ± 0.23	15.0 ± 11.0	7.5 × 104
2′,3′-cGMP	(2.9 ±0.6) × 10−4	1.02 ± 0.17	22.1 ± 11.4	7.6 × 104
3′,5′-cAMP	(1.3 ± 0.3) × 10−3	0.45 ± 0.04	9.2 ± 2.4	7.0 × 103
3′,5′-cGMP	(8.5 ± 2.1) × 10−4	0.37 ± 0.04	7.7 ± 2.9	9.0 × 103
YmdBE39Q
2′,3′-cAMP		≤0.05
2′,3′-cGMP		≤0.05
3′,5′-cAMP		≤0.05
3′,5′-cGMP		≤0.05