Heat and osmotic stress enhance the development of cytoplasmic serine proteinase activity in sporulating Bacillus megaterium.
The intracellular Ca(2+)-dependent serine proteinase (ISP1) activity in the cytoplasm of nongrowing Bacillus megaterium incubated in a sporulation medium was determined at 35 degrees C and at temperatures decreasing the sporulation frequency (42 degrees C) or suppressing sporulation (43.5 degrees C). The enzyme in the crude cytoplasmic fraction was partially inhibited by a loosely bound inhibitor(s) because the ISP1 activity rose after protein fractionation by HPLC. Temperature shift-up or osmotic stress applied at 35 degrees C increased the development of the ISP1 activity several times. The increase was caused at least partially by the synthesis of the enzyme protein, as proved by SDS-PAGE and immunoblotting of the cytoplasm. This enzyme thus probably belongs among heat-shock proteins.
Váchová
L
L
Department of Molecular and Cellular Microbiology, Academy of Sciences of the Czech Republic, Prague.
Kucerová
H
H
Benesová
J
J
Chaloupka
J
J
D001410:Bacillus megaterium / Q000201:enzymology* / Q000502:physiology; D002851:Chromatography, High Pressure Liquid; D003593:Cytoplasm / Q000201:enzymology; D004591:Electrophoresis, Polyacrylamide Gel; D004789:Enzyme Activation; D006360:Heat-Shock Proteins / Q000096:biosynthesis / Q000378:metabolism; D006358:Hot Temperature; D015151:Immunoblotting; D009997:Osmotic Pressure; D012697:Serine Endopeptidases / Q000096:biosynthesis / Q000378:metabolism*; D013171:Spores, Bacterial / Q000201:enzymology / Q000502:physiology; D013696:Temperature
D006360:Heat-Shock Proteins; D012697:Serine Endopeptidases