Cysteine protease that may play a role in regulating cell morphology in response to stressful conditions which likely cause oxidative damage. Appears to catalyze its own cleavage, which probably leads to its activation. Is inhibited by bromopyruvate in vitro. Activity is not affected by the presence of tellurite. Highly induced by starvation during long-term stationary phase, while shows very low expression during exponential growth. Is probably processed via an autocatalytic removal of a proregion of about 100 amino acids. Deletion of this gene causes hypersensitivity to tellurite, altered population dynamics during long term batch culture, and, most strikingly, dramatic alteration of normal cell morphology. Belongs to the cysteine protease StiP family.