Endopeptidase with broad substrate specificity for several oligopeptides. Binds 1 zinc ion per subunit. Strongly inhibited by 1,10-phenanthroline and phosphoramidon but relatively insensitive to EDTA. Not significantly inhibited by p-chloromercuribenzoate nor by phenylmethylsulfonyl fluoride. Optimum pH is 6.0-6.5. Optimum temperature is 30-38 degrees Celsius. Monomer. Belongs to the peptidase M13 family.