Purification and characterization of a cephalosporinase from E. coli.

The isolation and properties of a beta-lactamase from E. coli are described, which hydrolyses the Cephalosporins of the third generation. The enzyme has been brought to high purity by precipitation with (NH4)2SO4, gel chromatography and affinity chromatography on Cephalosporin C bound to agarose. The enzyme has been characterized by evaluation of its molecular weight 39 000, isoelectric point (pH 7.2), pH-optimum (pH 8.4) and substrate profile. It accepts Ceftizoxime, Cefamandole, Cefazolin and Cefotaxime as substrates, but shows nearly no activity on Penicillin G, Cefoxitin and the Desacetylmetabolite of Cefotaxime.