Close amino acid sequence relationship between the new plasmid-mediated extended-spectrum beta-lactamase MEN-1 and chromosomally encoded enzymes of Klebsiella oxytoca

Biochim Biophys Acta. 1992 Jul 13;1122(1):15-22. doi: 10.1016/0167-4838(92)90121-s.


Isolated from an Escherichia coli strain MEN-1 is a plasmid-mediated beta-lactamase that confers resistance to methoxy imino third-generation cephalosporins. The protein purified to homogeneity was digested by trypsin, chymotrypsin and endoproteinase Asp-N. Amino acid sequence determinations of the resulting peptides gave rise to the alignment of the 263 residues of the beta-lactamase. From amino acid sequence comparison MEN-1 was found to share more than 72% identity with the chromosomally mediated beta-lactamases of Klebsiella oxytoca. Therefore, MEN-1 is the first transferable extended-spectrum beta-lactamase which is not directly derived from the widespread TEMs or SHV-1 penicillinases with which it presents less than 39% identity.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Cephalosporins / metabolism
  • Escherichia coli / enzymology*
  • Escherichia coli / genetics
  • Klebsiella / enzymology*
  • Molecular Sequence Data
  • Peptide Fragments / isolation & purification
  • Plasmids
  • Sequence Alignment
  • Sequence Homology, Nucleic Acid
  • beta-Lactamases / chemistry
  • beta-Lactamases / isolation & purification*
  • beta-Lactamases / metabolism


  • Cephalosporins
  • Peptide Fragments
  • beta-Lactamases