Purification and properties of a new beta-lactamase from Streptomyces UCSM-104

Extracellular beta-lactamase was produced in larger amounts by Streptomyces UCSM-104 than by Streptomyces albus G or strains R-39 and K-11. The anionic character displayed by the enzyme from Streptomyces USCM-104 on DEAE-cellulose chromatography was consistent with its mobility in polyacrylamide gel electrophoresis. This beta-lactamase is a low molecular weight (14,800) globular protein having approximately 124 amino acid residues. The enzyme behaved as a penicillinase toward several substrates studied, being most active on benzylpenicillin and ampicillin. On the other hand, it was inhibited by methicillin and cloxacillin, which behaved as competitive inhibitors for the hydrolysis of benzylpenicillin and cephaloridine.