Virulence factor that contributes to intimate adherence of enterohemorrhagic E.coli (EHEC) O157:H7 to host cells. Is able to cleave the secreted human mucin 7 (MUC7) and the glycoprotein 340 (DMBT1/GP340). Also cleaves human C1 inhibitor (SERPING1), a regulator of multiple inflammatory pathways, and binds and localizes it to bacterial and host cell surfaces, protecting them from complement-mediated lysis. Therefore, the current model proposes two roles for StcE during infection: it acts first as a mucinase, allowing passage of EHEC through the oral cavity by cleaving the salivary glycoproteins that are responsible for bacterial aggregation. Similarly, in the colon, StcE cleaves the glycoproteins that protect the intestinal epithelial surface, allowing EHEC to come into close contact with host cell membranes. Secondly, it acts as an anti-inflammatory agent by localizing SERPING1 to cell membranes. Binds 1 zinc ion per subunit. Does not contain structural calcium, which is often associated with other metalloproteases. Inhibited by divalent cation chelators such as BPS and EDTA. Proteolytic activity is 2.5-fold more efficient with the secreted mucin MUC7 than with SERPING1. Optimum pH is 6.5-7.0. Active from pH 6.1 to 9.0. Optimum temperature is 37-42 degrees Celsius. Active from 4 to 55 degrees Celsius. Inactive above 60 degrees Celsius. Secreted via the etp type II secretion pathway. Up-regulated by the LEE (locus of enterocyte effacement)-encoded regulator ler. Is resistant to proteolytic degradation by trypsin, chymotrypsin, human and bacterial elastase, but not by the fungal protease proteinase K. Cleavage of SERPING1 occurs within its heavily glycosylated N-terminal region and is different to that of elastase.