TABLE 3

Catalytic efficiency values for mutant and wild-type SHV and TEM β-lactamases

SHV-1SHV R164SSHV D179GTEM-1aTEM R164SbTEM D179G
kcat/Km (M–1 s–1)
    AMP34.5 × 10642.3 × 1060.08 0.01 × 10629 × 106NA1.1 × 106
    Ceph1.4 × 1060.027 × 106NM1.36 × 1060.46 × 106NM
    CTX0.25 × 1060.0042 × 1060.005 × 1060.0016 × 1060.010 × 1060.005 × 106
    CAZ6841703373355.15200740
Relative kcat/Km
    AMP11.230.0020.84NA0.030
    Ceph10.019NM0.970.33NM
    CTX10.0170.0200.00640.040.020
    CAZ12.55.50.081 (1)7.6 (94)1.14 (14)

NA, not available; NM, not measured.

  • a Cantu et al. (1997).

  • b Bradford et al. (1994).