Interacts with hemoglobin, degrades it and subsequently binds the released heme. Could make heme accessible not only for E.coli, but also for B.fragilis during mixed intra-abdominal infections. Has a role in abscess formation. Protease activity is inhibited by 3,4-dichloroisocoumarin. Optimum pH is 6.0. The cleaved C-terminal fragment (autotransporter domain) is localized in the outer membrane. The signal peptide, cleaved at the inner membrane, guides the autotransporter protein to the periplasmic space. Then, insertion of the C-terminal translocator domain in the outer membrane forms a hydrophilic pore for the translocation of the passenger domain to the bacterial cell surface, with subsequent cleavage. Cleaved to release the mature protein from the outer membrane.