An additional ionic bond suggested by molecular modelling of TEM-2 might induce a slight discrepancy between catalytic properties of TEM-1 and TEM-2 beta-lactamases

FEMS Microbiol Lett. 1996 Oct 1;143(2-3):121-5. doi: 10.1111/j.1574-6968.1996.tb08470.x.


The plasmid-mediated TEM-1 and TEM-2 beta-lactamases are the most commonly encountered among Gram-negative bacteria. They belong to molecular class A, and differ by one amino acid at position 39:TEM-1 have a glutamine and TEM-2 a lysine. Kinetic parameters (kcat and Km) and catalytic efficiency (kcat/Km) of TEM-1 and TEM-2 beta-lactamases are slightly, but significantly different. For all antibiotics except methicillin and cefazolin, the catalytic efficiency values of TEM-2 are clearly greater than that of TEM-1. Molecular modelling of TEM-2, when compared to that of TEM-1, showed an additional ionic bond between Lys-39 and Glu-281.

Publication types

  • Comparative Study

MeSH terms

  • Catalysis
  • Escherichia coli / enzymology
  • Escherichia coli / genetics
  • Gram-Negative Bacteria / enzymology
  • Gram-Negative Bacteria / genetics
  • Kinetics
  • Models, Molecular
  • Molecular Structure
  • Protein Conformation
  • beta-Lactamases / chemistry*
  • beta-Lactamases / genetics
  • beta-Lactamases / metabolism


  • beta-Lactamases
  • beta-lactamase TEM-1
  • beta-lactamase TEM-2