Thiol protease. Acts synergistically with RgpA to catalyze the maturation of fimbrial subunits, such as FimA (PubMed:9786913). Its proteolytic activity is a major factor in both periodontal tissue destruction and in evasion of host defense mechanisms (By similarity). Hydrolysis of proteins and small molecule substrates, with a preference for Arg in P1. Belongs to the peptidase C25 family.