Enzyme kinetics and biochemical analysis of ImiS, the metallo-β-lactamase from Aeromonas sobria 163a

Abstract

The metallo-β-lactamase from Aeromonas sobria 163a, ImiS, was isolated in a two stage purification procedure using protein affinity columns. Enzyme kinetics show that ImiS hydrolyses the carbapenems but displays poor activity against other β-lactams. ImiS possesses the narrowest spectrum of activity of the Group 3 enzymes that have been analysed. Sequencing of the 40 N-terminal amino acids show this region to be identical to that of the CphA metallo-β-lactamase from Aeromonas hydrophila. Light scattering analysis indicates that ImiS is functionally active as a monomer.