Co-existence of beta-lactamase and penicillin acylase in bacteria; detection and quantitative determination of enzyme activities.

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.