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Vesicle penicillinase of Bacillus licheniformis 749/C. Apparent identity with the plasma membrane enzyme
Abstract:
A substantial fraction of the total membrane penicillinase of Bacillus licheniformis 749/C is attached to the vesicles released during conversion of the cells to protoplasts. This enzyme was purified since there was indirect evidence that it differed from the enzyme that remained with the protoplast. The purified vesicle penicillinase has the same molecular weight and general properties as the plasma membrane (protoplast) enzyme and, similarly, contains a covalently linked phosphatidylserine residue. Treatment of the two enzymes with trypsin produced phosphatidylserine-containing peptides which could not be distinguished by gel or paper electrophoresis. The two membrane penicillinases are very similar, if not identical.
Insights
Vesicle penicillinase from Bacillus licheniformis 749/C, released during protoplast conversion, was purified. This membrane enzyme is highly similar, if not identical, to the penicillinase remaining with the protoplast.
Area of Science:
- Microbiology
- Enzymology
- Biochemistry
Background:
- Bacillus licheniformis 749/C produces membrane penicillinase.
- Penicillinase is released in vesicles during cell-to-protoplast conversion.
- Evidence suggested vesicle-associated penicillinase might differ from protoplast-associated enzyme.
Purpose of the Study:
- To purify and characterize the vesicle-associated penicillinase.
- To compare vesicle penicillinase with the penicillinase remaining in the protoplast.
- To determine if these two membrane penicillinases are distinct entities.
Main Methods:
- Purification of vesicle-associated penicillinase from Bacillus licheniformis 749/C.
- Biochemical characterization including molecular weight determination.
- Enzymatic treatment with trypsin followed by electrophoretic analysis.
Main Results:
- Purified vesicle penicillinase shares identical molecular weight and general properties with protoplast penicillinase.
- Both enzymes contain a covalently linked phosphatidylserine residue.
- Trypsin treatment yielded indistinguishable phosphatidylserine-containing peptides from both enzymes.
Conclusions:
- The penicillinase released in vesicles is not significantly different from the penicillinase associated with the plasma membrane of the protoplast.
- The two membrane penicillinases of Bacillus licheniformis 749/C are essentially identical.
- This finding clarifies the nature and localization of membrane penicillinase in this bacterium.