Displays serine protease activity. Seems to have a broad substrate specificity. Is completely inhibited by phenylmethanesulphonylfluoride (PMSF) in vitro. Is leaked to the culture medium during the late stationary phase owing to cell lysis. Is expressed during the late stationary phase of growth. Is down-regulated by SinR. Cells lacking this gene show normal growth and sporulation. Belongs to the peptidase S8 family.