TABLE 2.

Kinetic parameters of the purified POM for the hydrolysis of various β-lactam substrates, in comparison with those of other subclass B3 MBLs^a

Substrate	kcat (mean ± SE) (s−1)			Km (mean ± SE) (μM)			kcat/Km (M−1 s−1)
	POM-1	L1	AIM-1	POM-1	L1	AIM-1	POM-1	L1	AIM-1	SMB-1	CAR-1	THIN-B	CAU-1	BJP-1	FEZ-1	GOB-1
Ampicillin	190 ± 6	175	594	23 ± 3	40	41	8.1 × 106	4.4 × 106	1.4 × 106	2.4 × 106	3.2 × 103	3.7 × 105	5.0 × 105	1.9 × 104	1.1 × 104	—b
Ticarcillin	190 ± 6	375	—	500 ± 46	140	—	3.9 × 105	2.7 × 106	—	—	1.3 × 104	—	—	—	1.3 × 104	5.2 × 105
Piperacillin	9 ± 0.3	140	337	53 ± 8	20	17	1.7 × 105	7.0 × 106	2 × 107	1.8 × 105	2.6 × 104	2.0 × 105	5.7 × 105	6.7 × 104	1.2 × 104	1.7 × 106
Cephalothin	60 ± 0.5	—	529	7 ± 0.3	—	38	8.9 × 106	—	1.4 × 107	1.9 ×106	1.2 × 106	—	4.3 × 105	5.8 × 105	2.5 × 106	6.7 × 105
Cefotaxime	56 ± 2	66	609	63 ± 6	26	49	9.0 × 105	2.6 × 106	1.2 × 107	8.9 × 105	1.5 × 106	2.0 × 106	—	1.4 × 105	2.4 × 106	8.5 × 105
Ceftazidime	>4	—	7	>800	—	148	5.3 × 103	1.8 × 105	4.9 × 104	7.7 × 104	2.9 × 105	1.4 × 105	2.0 × 103	4.3 × 103	4.0 × 103	7.6 × 105
Cefepime	>1.7	>15	93	>140	>1,000	594	1.2 × 104	1.9 × 104	1.6 × 105	3.6 × 103	—	7.9 × 103	—	2.0 × 102	6.0 × 103	2.0 × 105
Imipenem	312 ± 7	75	1,700	52 ± 3	100	97	6.0 × 106	7.5 × 105	1.7 × 107	3.9 × 106	—	1.5 × 106	2.0 × 105	6.0 × 104	2.0 × 105	6.6 × 105
Panipenem	500 ± 26	—	—	102 ± 4	—	—	4.9 × 106	—	—	—	—	—	—	—	—	—
Meropenem	220 ± 3	45	1,000	16 ± 1	10	163	1.4 × 107	4.5 × 106	6.8 × 106	4.2 × 106	9.6 × 102	5.0 × 106	2.6 × 105	8.3 × 105	5.0 × 105	5.3 × 106
Ertapenem	69 ± 6	—	—	4 ± 0.5	—	—	1.5 × 107	—	—	—	—	—	—	—	—	—
Doripenem	51 ± 4	—	—	7 ± 0.7	—	—	6.8 × 106	—	—	—	—	—	—	—	—	—

^aData for the subclass B3 MBLs are from references 12 and 13 (L1), 14 (THIN-B), 15 (AIM-1), 16 (SMB-1), 17 (GOB-1), 18 (FEZ-1), 19 (BJP-1), 20 (CAU-1), and 21 (CAR-1). Individual kinetic parameters are the means of three measurements.

^b—, not reported.