TABLE 1.

IC₅₀ and K_i (preincubation) values (μM) of clavulanic acid and AM-112 against isolated β-lactamase enzymes

Enzyme (group/classa) and inhibitor	IC50	Ki (pre-inc.b)
E. coli
TEM-1 (2b/A)
Clavulanic acid	0.12	7.1 × 10−4
AM-112	2.26	0.014
TEM-10 (2be/A)
Clavulanic acid	0.03	2.5 × 10−5
AM-112	0.224	5.6 × 10−5
SHV-5 (2be/A)
Clavulanic acid	0.008	1 × 10−5
AM-112	0.16	2 × 10−4
E. cloacae
P99 (1/C)
Clavulanic acid	11	0.009
AM-112	0.002	1.6 × 10−6
S. marcescens
S2 (1/C)
Clavulanic acid	327	0.15
AM-112	0.07	3 × 10−5
P. aeruginosa
S + A (1/C)
Clavulanic acid	449	0.086
AM-112	0.002	3.6 × 10−7
E. coli
OXA-1 (2d/D)
Clavulanic acid	99	2.3
AM-112	0.005	1.1 × 10−4
OXA-5 (2d/D)
Clavulanic acid	202	0.322
AM-112	0.0007	1 × 10−6

^aGroup, Bush-Jacoby-Medeiros classification (4); class, Ambler classification (1).

^bpre-inc., preincubation.