Bacillus megaterium spore protease: purification, radioimmunoassay, and analysis of antigen level and localization during growth, sporulation, and spore germination.

The protease which initiates the massive protein degradation early in bacterial spore germination has been purified from Bacillus megaterium spores. The enzyme has a molecular weight of 160,000 and contains four apparently identical subunits, but only the tetramer is enzymatically active. A radioimmunoassay has been developed for this enzyme and has been used to show that the protease is absent from growing cells, but appears early in sporulation within the developing forespore. In contrast, the protease antigen disappears rapidly during spore germination, in parallel with the loss in enzyme activity.