One of the virulence factors produced during swarmer cell differentiation of the bacteria, which seems to be associated with pathogenesis. The protease activity is limited to IgA1, IgA2, as well as IgG degradation. Preferential cleavage of bonds with hydrophobic residues in P1'. Binds 7 Ca(2+) ions per subunit. Binds 1 zinc ion per subunit. Ca(2+) increases protease activity. The Gly-rich repeats may be important in the extracellular secretion of this metalloprotease. Belongs to the peptidase M10B family.