Table 2.

Steady-state kinetic parameters for wildtype and mutant KPC-2 enzymes

KPC mutants		AMP	PenG	CEP	IMI	MER
KPC-2	kcat (s−1)	65 ± 2	19 ± 1	170 ± 10	48 ± 1	3.4 ± 0.1
	Km (μM)	380 ± 30	46 ± 5	120 ± 10	220 ± 20	24 ± 1
	kcat/Km (μM−1s−1)	0.17 ± 0.02	0.41 ± 0.06	1.42 ± 0.13	0.22 ± 0.04	0.14 ± 0.04
F72Y	kcat (s−1)	100 ± 10	9.8 ± 0.3	1.3 ± 0.1	0.15 ± 0.01	0.01 ± 0.002
	Km (μM)	90 ± 10	27 ± 3	5.2 ± 1	0.51 ± 0.05	1.8 ± 0.1
	kcat/Km (μM−1s−1)	1.1 ± 0.17	0.36 ± 0.05	0.25 ± 0.07	0.29 ± 0.04	0.006 ± 0.001
T215P	kcat (s−1)	460 ± 20	200 ± 10	190 ± 10	0.4 ± 0.01	0.16 ± 0.01
	Km (μM)	460 ± 40	480 ± 50	380 ± 40	1.8 ± 0.2	11 ± 2
	kcat/Km (μM−1s−1)	1.0 ± 0.15	0.42 ± 0.06	0.50 ± 0.07	0.23 ± 0.02	0.015 ± 0.003
Q128H	kcat (s−1)	340 ± 20	45 ± 2	270 ± 10	8.8 ± 0.2	0.89 ± 0.01
	Km (μM)	550 ± 70	160 ± 20	240 ± 10	16.6 ± 1.3	4.1 ± 0.3
	kcat/Km (μM−1s−1)	0.62 ± 0.10	0.28 ± 0.05	1.13 ± 0.08	0.53 ± 0.05	0.22 ± 0.02
R220H	kcat (s−1)	360 ± 10	130 ± 10	660 ± 20	20 ± 0.3	0.51 ± 0.03
	Km (μM)	290 ± 20	180 ± 20	290 ± 30	33 ± 2	2.5 ± 0.4
	kcat/Km (μM−1s−1)	1.2 ± 0.11	0.72 ± 0.12	2.3 ± 0.07	0.61 ± 0.04	0.20 ± 0.04
T237Aa	kcat (s−1)	150 ± 10	12 ± 1	47 ± 1	8.9 ± 0.3	0.11 ± 0.01
	Km (μM)	17 ± 2	19 ± 2	51 ± 4	19 ± 2	1.3 ± 0.24
	kcat/Km (μM−1s−1)	8.8 ± 0.1	0.63 ± 0.09	0.92 ± 0.08	0.47 ± 0.06	0.09 ± 0.02
S106P	kcat (s−1)	120 ± 10	12 ± 1	64 ± 2	22 ± 0.3	2.0 ± 0.1
	Km (μM)	1150 ± 80	50 ± 6	210 ± 20	220 ± 10	28 ± 2
	kcat/Km (μM−1s−1)	0.10 ± 0.01	0.24 ± 0.04	0.30 ± 0.04	0.10 ± 0.01	0.07 ± 0.01
A126T	kcat (s−1)	180 ± 10	16 ± 1	93 ± 2	27 ± 1	2.5 ± 0.1
	Km (μM)	1550 ± 60	60 ± 10	240 ± 10	200 ± 20	30 ± 2
	kcat/Km (μM−1s−1)	0.12 ± 0.01	0.27 ± 0.06	0.39 ± 0.03	0.14 ± 0.02	0.08 ± 0.01

AMP, ampicillin; CEP, cephalothin; IMI, imipenem; MER, meropenem; PenG, benzylpenicillin.

^aT237A kinetic parameters for ampicillin, cephalothin, imipenem an meropenem are from Mehta et al. (2020).