A beta-lactamase from Serratia marcescens hydrolyzing the 2-carboxypenam T-5575

A beta-lactamase was purified from Serratia marcescens GN16694; it hydrolyzed T-5575 and oxime-type cephalosporins, i.e., cefuroxime and ceftazidime. Its isoelectric point and molecular weight were 8.6 and 42,000, respectively. This enzyme was not inhibited by EDTA and clavulanic acid. This enzyme is an unusual beta-lactamase and has been classified as a group 1 cephalosporinase.