title: Activation of the intracellular Ca(2+)-dependent serine protease ISP1 of bacillus megaterium by purification or by high Ca2+ concentrations.
abstract: The total proteolytic activity of ISP1 determined after its partial purification by size exclusion HPLC increased 3.0, 7.3 and 27.3 times in sporulating, growing and netropsin-treated cells, respectively, as compared with the corresponding original activity in crude cytoplasmic preparations at the same CaCl2 concentration of 3 mM. A similar rise in proteolytic activity occurred on increasing the Ca2+ concentration in the crude cytoplasm from 3 to 30 mM. This activation in the cytoplasm of netropsin-treated and sporulating cells was not reversed by subsequent lowering of CaCl2 concentration back to 3 mM by dialysis. Moreover, a similar activation appeared even after the same dialysis of cytoplasm that had not been exposed to 30 mM CaCl2. The activation was probably due to the processing of ISP1, as established by SDS-PAGE and immunoblotting, but an involvement of additional regulation factor(s), e.g. an inhibitor or other molecules, is possible.
authors.affiliation: Department of Cell and Molecular Microbiology, Academy of Sciences of the Czech Republic, Prague, Czech Republic.
authors.forename: L
authors.initials: L
authors.lastname: Váchová
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001410:Bacillus megaterium / Q000201:enzymology* / Q000254:growth & development / Q000502:physiology; D002118:Calcium / Q000378:metabolism / Q000494:pharmacology*; D002122:Calcium Chloride / Q000494:pharmacology; D004789:Enzyme Activation; D008970:Molecular Weight; D009429:Netropsin / Q000494:pharmacology; D010664:Phenylmethylsulfonyl Fluoride / Q000494:pharmacology; D012697:Serine Endopeptidases / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D013171:Spores, Bacterial
chemical_list: D000900:Anti-Bacterial Agents; D010664:Phenylmethylsulfonyl Fluoride; D009429:Netropsin; D012697:Serine Endopeptidases; D002122:Calcium Chloride; D002118:Calcium