TABLE 2

Km and kcat values for SHV-1, SHV Arg164Asp, SHV Arg164Ser, TEM1, and TEM Arg164Ser

SHV-1SHV R164SSHV D179GTEM-1aTEM R164SbTEM D179G
Kmm)
    AMP54 ± 14.65.4 ± 0.526.6 ± 5.950 ± 2NA8± 2
    Ceph242.12 ± 17.4178.5 ± 55NMd697 ± 12100NMd
    CTX240.5 ± 24175.6 ± 68527.8 ± 5711002301783 ± 422
    CAZNMcNMc168.2 ± 18NMc270 × 103NMc
kcat (s–1)
    AMP1773 ± 126227.8 ± 8.62 ± 0.11428 ± 24NA8.24 ± 0.3
    Ceph331.9 ± 14.94.6 ± 0.64NMd947 ± 946NMd
    CTX58.7 ± 30.68 ± 0.12.6 ± 0.151.82.32.6 ± 0.15
    CAZNMcNM0.63 ± 0.04NMc1.4NMc

NA, not available.

  • a Cantu et al. (1997).

  • b Bradford et al. (1994).

  • c NM, not measured. Only catalytic efficiency was measured by assuming Embedded Image and therefore V = (kcat/Km) × [E] [S].

  • d Cephaloridine was no longer commercially available.