Table 3.

Kinetic parameters of wild-type and mutant β-lactamase catalysis of ampicillin hydrolysis^*

Sample	kcat (s−1)	Km, μM	10−7 × kcat/Km, M−1·s−1	Ratio†
Wild type	830  ± 30	58  ± 1	1.4	1.00
L76N	660  ± 13	150  ± 5	0.43	0.30
M182T	820  ± 50	59  ± 7	1.4	0.96
L76N/M182T	820  ± 40	110  ± 10	0.8	0.53

^*The kinetic parameters were measured using ampicillin as the substrate as described in Materials and Methods. 

^† Ratio of k_cat/K_m of mutant relative to wild-type β-lactamase.