. 2008 Jun 2;52(8):2977–2979. doi: 10.1128/AAC.00175-08

TABLE 2.

Kinetic parameters of VIM-15, VIM-16, and VIM-2^a

Substrate	VIM-15					VIM-16					VIM-2
Substrate	k_cat (s⁻¹)	Relative^bk_cat	K_m (μM)	k_cat/K_m (s⁻¹ μM⁻¹)	Relative^bk_cat/K_m	k_cat (s⁻¹)	Relative^bk_cat	K_m (μM)	k_cat/K_m (s⁻¹ μM⁻¹)	Relative^bk_cat/K_m	k_cat (s⁻¹)	Relative^bk_cat	K_m (μM)	k_cat/K_m (s⁻¹ μM⁻¹)	Relative^bk_cat/K_m
Cephaloridine	190 ± 4	100	83 ± 2	2.3	100	89 ± 2	100	1400 ± 53	0.064	100	120 ± 5	100	1400 ± 6	0.086	100
Benzylpenicillin	240 ± 3	130	25 ± 0.5	9.6	420	230 ± 24	260	450 ± 8	0.51	800	73 ± 0.4	61	150 ± 1	0.49	570
Cefepime	9.5 ± 0.1	5.0	130 ± 2	0.076	3.3	0.31 ± 0.03	0.35	210 ± 1	0.0015	2.3	0.38 ± 0.02	0.32	110 ± 6	0.0035	4.1
Ceftazidime	1.0 ± 0.04	0.53	37 ± 2	0.027	1.2	0.22 ± 0.00	0.25	150 ± 2	0.0014	2.2	0.23 ± 0.01	0.19	150 ± 6	0.0015	1.7
Cefotaxime	90 ± 7	47	13 ± 1	6.9	300	81 ± 0.2	91	240 ± 9	0.34	530	NT	NT	NT	NT	NT
Imipenem	61 ± 2	32	7.3 ± 0.5	8.4	370	45 ± 2	51	89 ± 2	0.51	800	20 ± 0.3	17	60 ± 2	0.33	380
Meropenem	6.5 ± 0.05	3.4	3.4 ± 0.5	1.9	83	8.4 ± 0.3	9.4	120 ± 5	0.070	110	2.1 ± 0.1	1.8	40 ± 2	0.053	62
Aztreonam^c	≤0.031	≤0.016	ND	ND	ND	≤0.11	≤0.12	ND	ND	ND	NT	NT	NT	NT	NT

NT, not tested; ND, not determined as hydrolysis was too slow to determine K_m.

The cephaloridine value was taken as 100%.

Hydrolysis of aztreonam was very slow; V_max was estimated as 2 times the maximum hydrolysis rate observed.