Cleaves host elastin, collagen, IgG, and several complement components as well as endogenous pro-aminopeptidase (PubMed:11533066). Autocatalyses processing of its pro-peptide (PubMed:9642203, PubMed:1744034). Processes the pro-peptide of pro-chitin-binding protein (cbpD) (PubMed:9642203). Involved in the pathogenesis of P.aeruginosa infections. Hydrolysis of proteins including elastin, collagen types III and IV, fibronectin and immunoglobulin A, generally with bulky hydrophobic group at P1'. Insulin B chain cleavage pattern identical to that of thermolysin, but specificity differs in other respects. Binds 1 Ca(2+) ion per subunit. Binds 1 Zn(2+) ion per subunit. Inhibited by phosphoramidon. Monomer. Secreted in an Xcp-dependent fashion (a type II secretion pathway). Optimal protein expression in vivo requires both Zn(2+) and Ca(2+) during growth (at protein level). Made as a membrane-associated pre-pro-protein, which is exported to the periplasm (yielding pro-elastase) with removal of the signal peptide. Under certain conditions pro-elastase can accumulate. The pro-peptide is removed in the periplasm yielding a (mature length) 33 kDa protein, probably by autocatalysis (PubMed:1744034). The pro-peptide probably remains associated with elastase and can be secreted (PubMed:9642203). Further alterations (perhaps processing) seems to be required before secretion into the extracellular space (PubMed:1744034). Loss of processing of its own pro-peptide and pro-chitin-binding protein CbpD (PubMed:9642203). Loss of processing of pro-aminopeptidase to mature aminopeptidase (PubMed:11533066). Belongs to the peptidase M4 family.