Study of a Natural Mutant SHV-Type β-Lactamase, SHV-104, from Klebsiella pneumoniae

Table 3

Kinetics parameters.

Antibiotics	SHV-104			SHV-1
	𝑘cat	Km	𝑘cat/Km	𝑘cat	Km	𝑘cat/Km
	(sec^−1)	(𝜇M)	(𝜇M^−1 sec^−1)	(sec^−1)	(𝜇M)	(𝜇M^−1 sec^−1)
Benzylpenicillin	55	94	0.6	360	20	18
Ticarcillin	80	10	8	80	27	3
Nitrocefin	830	43	19	290^a	21^a	14^a
Cephalothin	30	68	0.44	9	30	0.3
Cefuroxime	0.53	540	0.001	0.5	100	0.005
Cefotaxime	>1.8	>600	0.003	N.D.	N.D.	N.D.

ND: not determinable because the hydrolysis rate was too low.
aThe kinetic constants of nitrocefin for SHV-1 are from Thomson et al. [10].