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Penicillin amidohydrolases in fungal autolysis
C Alfonso1, L Cribeiro, F Reyes
1Centro de Investigaciones Biologicas, Consejo Superior de Investigaciones Cientificas, Madrid, Spain.
Abstract:
The production of penicillin G and penicillin V amidohydrolases or acylases (E.C.3.5.1.11) was studied during the autolysis of filamentous fungi in a mineral medium, and in the same medium with phenoxyacetic acid as inducer. In all the studied fungi, enzymes showing penicillin G and penicillin V amidohydrolase activities were found. Generally, an increase of these activities during fungal autolysis was observed. The presence of phenoxyacetic acid in the medium did not increase these activities. The activities found in the culture fluids were generally higher than that found in the mycelial extracts. Under these conditions, beta-lactamases (penicillinases) were not found. The fungi Alternaria alternata, Fusarium culmorum, Penicillium oxalicum, and the species Penicillium 222 were chosen to study penicillin G and penicillin V acylases. The enzymes were precipitated with tannic acid from the culture fluid of their autolyzed cultures. Some kinetic constants of these activities were determined.
Insights
Filamentous fungi produce penicillin amidohydrolases (acylases) during autolysis, with higher activity in culture fluids. Phenoxyacetic acid did not enhance enzyme production in this study.
Area of Science:
- Biochemistry
- Enzymology
- Mycology
Background:
- Penicillin amidohydrolases (E.C.3.5.1.11), also known as penicillin acylases, are crucial enzymes in penicillin processing.
- Filamentous fungi are known producers of various enzymes, including those involved in antibiotic modification.
Purpose of the Study:
- To investigate the production of penicillin G and penicillin V amidohydrolases during the autolysis of selected filamentous fungi.
- To determine the effect of phenoxyacetic acid as an inducer on enzyme production.
- To compare enzyme activity in culture fluids versus mycelial extracts and to characterize the enzymes.
Main Methods:
- Studied enzyme production during fungal autolysis in mineral medium with and without phenoxyacetic acid.
- Assayed penicillin G and penicillin V amidohydrolase activities.
- Compared activities in culture fluids and mycelial extracts.
- Precipitated enzymes using tannic acid and determined kinetic constants.
Main Results:
- All tested fungi exhibited penicillin G and penicillin V amidohydrolase activities.
- Enzyme activities generally increased during fungal autolysis.
- Phenoxyacetic acid did not enhance enzyme activities.
- Culture fluids showed higher enzyme activities than mycelial extracts.
- No beta-lactamases (penicillinases) were detected.
Conclusions:
- Filamentous fungi naturally produce penicillin amidohydrolases (acylases) during autolysis.
- Autolysis is a viable method for obtaining these enzymes, with culture fluid being the preferred source.
- The studied fungi, including Alternaria alternata and Penicillium species, are potential sources for penicillin acylase production.