TABLE 3.

Antibody inactivation studies of SHV-1 and CMY-2 β-lactamasesa

β-Lactamase/substrateAntibody:β-lactamase molar ratioVelocity (μM−1 s−1)% Decrease
Anti-SHV-1:SHV-1
3.5 nM SHV-1/Amp0:113.2 ± 1.1
3.5 nM SHV-1/Amp5:13.2 ± 0.276
3.5 nM SHV-1/Amp10:11.5 ± 0.189
3.5 nM SHV-1/Amp20:11.2 ± 0.191
Anti-CMY-2:SHV-1
3.5 nM SHV-1/Amp10:111.3 ± 0.414
3.5 nM SHV-1/Amp20:111.2 ± 0.215
Anti-SHV-1:SHV-1
18 nM SHV-1/NCF0:12.7 ± 0.2
18 nM SHV-1/NCF5:11.5 ± 0.142
18 nM SHV-1/NCF10:10.8 ± 0.169
18 nM SHV-1/NCF20:10.7 ± 0.176
Anti-CMY-2:SHV-1
18 nM SHV-1/NCF5:12.6 ± 0.10
18 nM SHV-1/NCF10:12.8 ± 0.10
18 nM SHV-1/NCF20:12.6 ± 0.10
Anti-CMY-2:CMY-2
3.5 nM CMY-2/Cefaz0:11.2 ± 0.1
3.5 nM CMY-2/Cefaz5:10.7 ± 0.142
3.5 nM CMY-2/Cefaz10:10.4 ± 0.0167
3.5 nM CMY-2/Cefaz20:10.4 ± 0.0367
Anti-SHV-1:CMY-2
3.5 nM CMY-2/Cefaz5:11.2 ± 0.030
3.5 nM CMY-2/Cefaz10:11.2 ± 0.010
3.5 nM CMY-2/Cefaz20:11.1 ± 0.030
Anti-CMY-2:CMY-2
18 nM CMY-2/NCF0:13.6 ± 0.03
18 nM CMY-2/NCF5:12.1 ± 0.0342
18 nM CMY-2/NCF10:10.5 ± 0.186
18 nM CMY-2/NCF20:10.7 ± 0.0181
Anti-SHV-1:CMY-2
18 nM CMY-2/NCF5:13.6 ± 0.10
18 nM CMY-2/NCF10:13.6 ± 0.10
18 nM CMY-2/NCF20:13.5 ± 0.10
Anti-CMY-2:E. cloacae
18 nM E. cloacae/NCF0:11.7 ± 0.02
18 nM E. cloacae/NCF10:10.2 ± 0.0388
Anti-CMY-2:C. freundii
5 nM C. freundii/NCF0:12.1 ± 0.1
5 nM C. freundii/NCF10:10.5 ± 0.0376
Anti-CMY-2:P. aeruginosa
18 nM P. aeruginosa/NCF0:15.2 ± 0.3
18 nM P. aeruginosa/NCF10:14.4 ± 0.316
  • a β-Lactamase was mixed with various molar ratios of either anti-SHV-1 or anti-CMY-2 antibody, as described in Materials and Methods. Each velocity determination was repeated in triplicate, and standard deviations were calculated. NCF, 100 μM nitrocefin; Amp, 500 μM ampicillin; Cefaz, 50 μM cefazolin. Percent decrease is relative to the velocity determined when no antibody was added.