TABLE 2.

Kinetic parameters of purified NDM enzymes^a

β-Lactam(s)	NDM-1			NDM-5			NDM-9			NDM-35
	kcat (s−1)	Km (μM)	kcat/Km (μM−1 · s−1)	kcat (s−1)	Km (μM)	kcat/Km (μM−1 · s−1)	kcat (s−1)	Km (μM)	kcat/Km (μM−1 · s−1)	kcat (s−1)	Km (μM)	kcat/Km (μM−1 · s−1)
Penicillin G	220	110	2	320	100	3.2	18	60	0.3	230	150	1.5
Amoxicillin	220	170	1.3	220	1,000	0.22	12	75	0.16	140	300	0.45
Ticarcillin	40	100	0.4	35	150	0.23	45	170	0.26	30	75	0.4
Cephalothin	290	20	14.5	60	10	6	1.2	5	0.24	55	11	5
Cefotaxime	200	20	10	160	25	6.4	15	20	0.75	65	65	1
Ceftazidime	810	>1,000	0.8	450	>1,000	0.45	105	>1,000	0.10	115	>1,000	0.1
Imipenem	50	50	1	430	110	4	35	90	0.4	50	50	1
Ertapenem	45	20	2.2	65	65	1	20	12	1.7	70	60	1.2
Meropenem	35	40	0.85	550	80	6.8	27	27	1	90	45	2
Cefiderocol	0.9	280	0.003	0.7	230	0.003	4.6	200	0.02	7	270	0.03

^aStandard deviations were below 15%. k_cat, catalytic efficiency; K_m, Michaelis constant; k_cat/K_m, specificity constant.