Thiol protease which shows activity against the fluorogenic substrate z-Arg-Arg-AMC. Secreted from animals irradiated with ultraviolet or ionizing gamma rays into the culture medium. Not detected in the embryo, observed in the intestine of early stage L1-L3 larvae, peaks at the L4 larval stage and declines in adulthood. Induced by ultraviolet and ionizing radiation through a cep-1-dependent mechanism. RNAi-mediated knockdown results in greatly reduced radiation-induced bystander effect (RIBE) activity in the culture medium of irradiated animals. Mediates the radiation-induced bystander effect (RIBE), a process in which factors released by irradiated cells or tissues exert effects on unexposed cells or tissues. Following localized ultraviolet irradiation of the head, mediates RIBE in multiple unexposed regions including the posterior region. Also leads to RIBE including inhibition of cell death and increased embryonic lethality of progeny in unirradiated animals exposed to the culture medium of irradiated animals. Likely to exert RIBE by acting through the insulin-like receptor daf-2. Belongs to the peptidase C1 family.