Table 2.

Characteristics of SHV-type β-lactamasesa

pIEnzymesEnzyme type
Broad spectrumESBLInhibitor resistant
7.0OHIO-1, LEN-1 X
SHV-3, SHV-14 X
7.5 SHV-24X
7.6 SHV-1, SHV-11 X
SHV-2, SHV-2a, SHV-6, SHV-8, SHV-13, SHV-19, SHV-20, SHV-21, SHV-22 X
7.8 SHV-4, SHV-7b, SHV-18 X
8.2 SHV-5, SHV-9, SHV-12 X
  • a Amino acid sequences for TEM, SHV, and OXA extended-spectrum and inhibitor-resistant β-lactamases may be found at All enzymes listed are naturally occurring mutants.

  • b SHV-7 was reported to have a pI of 7.6 (27), but further examination of this enzyme indicates that the pI is most likely to be 7.8. This enzyme shows an interesting phenomenon in that the isoelectric point varies depending on the day of testing and the purity of the enzyme (unpublished observations).