The zymogen of the protease that degrades small, acid-soluble proteins of spores of Bacillus species can rapidly autoprocess to the active enzyme in vitro.

The zymogen of the protease (GPR) that initiates protein degradation during spore germination in Bacillus species is not activated in vitro under normal physiological conditions. However, there is rapid, acid-pH-dependent, zero-order, proteolytic activation of the purified zymogen in high concentrations of dimethyl sulfoxide. These findings provide further evidence that GPR activates itself during sporulation.