TABLE 4

Kinetic parameters of the NDM-1, NDM-1I35T, and NDM-1I35S enzymes for some β-lactams

SubstrateNDM-1NDM-1I35TNDM-1I35S
Km (μM)kcat (s−1)kcat/Km (μM s−1)Km (μM)kcat (s−1)kcat/Km (μM s−1)Km (μM)kcat (s−1)kcat/Km (μM s−1)
Benzylpenicillin250 ± 101050.42250 ± 10580.23380 ± 231300.34
Carbenicillin285 ± 51080.38650 ± 36620.09680 ± 301630.24
Imipenem35 ± 1641.8342 ± 324.50.5890 ± 61071.19
Meropenem80 ± 2750.9490 ± 5270.3060 ± 4350.58
Biapenem120 ± 4300.25300 ± 8190.061,000 ± 401410.14
Cefazolin20 ± 1422.1014 ± 2120.8621 ± 3280.90
Cefoxitin26 ± 1230.8818 ± 1110.6165 ± 4440.68
Cefaclor30 ± 2311.0335 ± 3120.3414 ± 160.43
Loracarbef40 ± 2421.059 ± 1303.334 ± 0.55614.0
Moxalactam22 ± 1150.6850 ± 770.1460 ± 5170.28
Cefotaxime14 ± 1201.438 ± 350.633 ± 0.3113.67
Ceftazidime50 ± 418.50.3744 ± 560.1440 ± 2110.28
Cefepime35 ± 5130.3740 ± 360.1532 ± 160.19
AztreonamNHaNHNHNHNHNHNHNHNH
Sulbactam1,400 ± 50500.0361,100 ± 45190.0171,300 ± 32660.05
Nitrocefin15 ± 3100.6721 ± 460.2920 ± 270.35
  • a NH, not hydrolyzed.