. Author manuscript; available in PMC: 2008 Aug 28.

Published in final edited form as: Biochemistry. 2006 Nov 7;45(44):13385–13393. doi: 10.1021/bi061238o

Table 2.

Steady-state kinetic constants for hydrolysis of substrates with oxygen (C6-HSL, O) or sulfur (C6-HCTL, S) leaving groups by AHL lactonase disubstituted with various divalent metal ions.^a

Metal Supplement	C6-HSL		C6-HCTL		$\frac{k_{c a t} (O)}{k_{c a t} (S)}$ ^b	$\frac{K_{M} (O)}{K_{M} (S)}$
Metal Supplement	k_cat (s⁻¹)	K_M (mM)	k_cat (s⁻¹)	K_M (mM)	$\frac{k_{c a t} (O)}{k_{c a t} (S)}$ ^b	$\frac{K_{M} (O)}{K_{M} (S)}$
MnSO₄	330 ± 20	0.18 ± 0.04	500 ± 20	0.39 ± 0.05	0.66 ± 0.07	0.4 ± 0.2
CoCl₂	510 ± 10	0.36 ± 0.04	198 ± 8	6.7 ± 0.7	2.6 ± 0.2	0.054 ± 0.006
ZnSO₂	91 ± 3	5.6 ± 0.6	4.1 ± 0.7	36 ± 10	22 ± 5	0.16 ± 0.06
CdCl₂	480 ± 20	0.24 ± 0.03	5.0 ± 0.5	0.12 ± 0.02	100 ± 20	2.0 ± 0.6

Reactions were carried out at pH 7.4, 28° C.

Ratios compare the relative steady-state kinetic constants for hydrolysis of substrates with an oxygen (O) leaving group, C6-HSL, or with a sulfur (S) leaving group, C6-HCTL.