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THE ROLE OF CALCIUM FOR STABILITY AND ACTIVITY OF AN EXTRACELLULAR PROTEOLYTIC ENZYME FROM STAPHYLOCOCCUS AUREUS
Author(s) -
Arvidson S.
Publication year - 1973
Publication title -
acta pathologica microbiologica scandinavica section b microbiology and immunology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.909
H-Index - 88
eISSN - 1600-0463
pISSN - 0365-5563
DOI - 10.1111/j.1699-0463.1973.tb02240.x
Subject(s) - protease , enzyme , casein , chemistry , extracellular , biochemistry , enzyme assay , staphylococcus aureus , calcium , substrate (aquarium) , molecular mass , chromatography , bacteria , biology , organic chemistry , ecology , genetics
The inactivation by EDTA of an extracellular protease, produced by Staphylococcus aureus , strain V8, was studied by the use of radioactive enzyme, gel chromatography and quantitative immunological methods. It was shown that the removal of Ca2+ from the enzyme by treatment with EDTA (5 mM) at 4° C resulted in irreversible loss of its activity on casein. This inactivation was not accompained by any measurable change in the molecular weight or immunoprecipitating properties of the protease. If treatment with EDTA were performed at 37° C, the loss of activity on casein would be followed by a subsequent loss of the immunoprecipitating properties of the enzyme, which was shown to be due to degradation of the enzyme. The degradation started after the loss of detectable enzyme activity. Thus it may be suggested that the removal of Ca2+ from the enzyme resulted in an altered tertiary structure of the protease in which the active site was hidden so that it could not reach the large substrate molecules i.e. casein and that, though inactive against casein, the calcium‐free enzyme was capable of degrading itself to peptides with molecular weights in the range 4,000–7,000.