TABLE 3.

Kinetic parameters for V. cholerae CARB-6 β-lactamase in comparison with the published values for β-lactamases TEM-1, SAR-1, and CARB-1 to CARB-3^a

Antibiotic	Km (μM)						Vm (relative)b
	CARB-6	SAR-1	TEM-1	CARB-1	CARB-2	CARB-3	CARB-6	SAR-1	TEM-1	CARB-1	CARB-2	CARB-3
Penicillin G	96	42	24	13	7.3	9.8	100	100	100	100	100	100
Amoxicillin	157	—c	43	13.6	16.4	21.8	266	—	84	63	128	97
Ampicillin	—	68	35	30	20.9	24	—	63	111	94.5	93	100
Ticarcillin	55	—	10	40	18.8	21	59	—	3	88	126	97
Carbenicillin	—	190	14	122	72	95	—	122	10	126	343	147
Piperacillin	7	—	43	—	—	—	15.9	—	86	—	—	—
Mezlocillin	58.5	—	246	15.5	14	20	100	—	100	86	83	111
Oxacillin	37	—	6	58	31	24.5	5.25	—	5	5.4	11.4	12.5
Cephaloridine	526	93	950	40.5	208	418	59.5	21	76	14.6	16	44.2
Cephalothin	—	—	—	—	—	—	<0.5	—	20	1.25	0.8	0.5

^aData for TEM-1 (21), SAR-1 (29), and CARB-1 to CARB-3 (16, 18) have been published previously. 

^bV_m is expressed as a percentage of hydrolysis of benzylpenicillin (for which the V_m is equal to 100), which was used as a reference. 

^c—, not determined.