Co‐existence of β‐lactamase and penicillin acylase in bacteria; detection and quantitative determination of enzyme activities

Abstract

Twenty-six bacteria were examined for the presence of penicillin acylase and beta-lactamase. A copper reducing assay, which was sensitive in the analytical range 2-20 micrograms/ml, was used for determination of penicilloates and a fluorescamine assay was used to determine 6-aminopenicillanic acid concentrations when both substances were produced by the action of the enzymes on a single substrate. Seventeen bacteria contained beta-lactamases, six contained penicillin acylases and four contained both enzymes. Two bacteria contained a Type 1 penicillin acylase and four bacteria contained a Type II enzyme. No ampicillin acylases were detected. All beta-lactamases were constitutive enzymes in those organisms where both enzymes co-existed. Bacillus subtilis and B. cereus produced inducible and extracellular beta-lactamases. Acinetobacter calcoaceticus ATCC 21288 produced a constitutive beta-lactamase which was detected extracellularly.

Development and characterization of a potent producer of penicillin G amidase by mutagenization

“…These strains are now known to acquire the ability to produce betalactamase that inhibits the activity of PGA (Salih & Saba 1989;Arshad et al 2000). Amidases of the Gram-negative bacteria are located in periplasm (Son et al 1982;Baker 1992). Strains with highly active amidase have outer membranes through which the penicillin G passes easily.…”

Mutagenic effect of acridine orange on the expression of penicillin G acylase and beta-lactamase in Escherichia coli

“…6‐APA into biologically inactive metabolites such as penicilloic acid and penicic acid (Ghuysen 1991), which render the β ‐lactam antibiotics ineffective (Frere 1995; Livermore 1995). The coexistence of PGA and β ‐lactamase in the same microbial strain (Baker 1992; Arshad and Saba 2001) limits the possibility of using whole cells as biocatalyst for the synthesis of 6‐APA.…”