Table 1.

Steady-state kinetic constants of recombinant L1 and metallo-β-lactamase isolated from S. maltophilia ULA-511

CompoundRecombinant L1ULA-511
Km (μM)kcat(s−1)kcat/Km (s−1μM−1)Km (μM)kcat(s−1)kcat /Km (s−1μM−1)BufferaReference
Piperacillin200 ± 20420 ± 202.120 ± 11407.1B 9
Ampicillin300 ± 15580 ± 201.940 ± 31754.4A 10
Cefuroxime130 ± 4053 ± 90.4130 ± 3802.7A 10
BRL42715600 ± 70170 ± 100.28270 ± 100.550.0020D 16
Penicillin G75 ± 10410 ± 205.550 ± 61,10022A 10
Cefprozil100 ± 2015 ± 10.15
Cefotaxime160 ± 20140 ± 90.8826 ± 3662.5A 10
Ticarcillin490 ± 100440 ± 700.90140 ± 23752.7B 9
Biapenem75 ± 1164 ± 40.8556 ± 1651.2C 12
Nitrocefin12 ± 131 ± 12.67 ± 1202.9A 10
Cephalothin43 ± 765 ± 31.590.9
Cefaclor31 ± 316 ± 10.52
Cephaloridine170 ± 3067 ± 50.39300 ± 50280.093A 10
Cephradine260 ± 4016 ± 10.06250 ± 512.50.25B 9
Ceftizoxime7.9 ± 1.62.7 ± 0.10.34
Cefoxitin3.3 ± 0.42.2 ± 0.10.672 ± 0.051.100.55A 10
Cefmetazole4.1 ± 0.24.7 ± 0.11.1
Cephalosporin C180 ± 18280 ± 131.625 ± 1622.5E 11
Clavulanic acid22 ± 211 ± 10.50
Moxalactam5 ± 10.15 ± 0.010.0301 ± 0.050.290.29A 10
Cefadroxil250 ± 5023 ± 20.092
Cefepime130 ± 300.33 ± 0.040.025>1,000>15.0B 9
Azlocillin59 ± 637 ± 20.636 ± 0.17513B 9
Cefsulodin32 ± 50.086 ± 0.0050.00275 ± 0.37.51.5B 9
  • a Buffer A was 50 mM sodium cacodylate, pH 7.0, containing 100 μM Zn(II) at 35°C. Buffer B was 30 mM sodium cacodylate, pH 6.5, containing 100 μM Zn(II) at 30°C. Buffer C was 30 mM sodium cacodylate, pH 6.5, containing 100 μM Zn(II) at 30°C. Buffer D was 50 mM sodium cacodylate, pH 7.0, containing 100 μM Zn(II) at 35°C. Buffer E was 30 mM sodium cacodylate, pH 7.0, containing 50 μM Zn(II) at 30°C.