Table 4.

Kinetic parameters of wild-type and P68G mutant IMP-6 and IMP-1

	IMP-6a			IMP-6-P68G
Antibiotic	k cat	K m	k cat/Km	k cat	K m	k cat/Km
	(s−1)	(μM)	(s−1·μM−1)	(s−1)	(μM)	(s−1·μM−1)
Imipenem	68	110	0.61	551	849	0.0.649
Meropenem	32	7.6	4.2	23.8	8.53	2.78
Penicillin G	51	220	0.23	141	28.5	0.495
Cephalothin	374	4.7	79.6	446	11.7	38.1
Cefotaxime	55	3.8	14.5	82.4	3.79	21.7
	IMP-1a			IMP-1-P68G
Antibiotic	k cat	K m	k cat/Km	k cat	K m	k cat/Km
	(s−1)	(μM)	(s−1·μM−1)	(s−1)	(μM)	(s−1·μM−1)
Imipenem	46	39	1.2	69.0	6.92	9.97
Meropenem	44	30	1.5	8.94	18.3	0.489
Penicillin G	330	520	0.62	657	1422	0.462
Cephalothin	48	21	2.4	46.0	7.57	6.08
Cefotaxime	1.3	4	0.35	16.5	11.4	1.48

^aValues reported by Yano et al. (15).