Belongs to the peptidase S1 family. Asn-56 is present instead of the conserved His which is expected to be an active site residue. Asn-102 is present instead of the conserved Asp which is expected to be an active site residue. Thr-196 is present instead of the conserved Ser which is expected to be an active site residue. It is therefore expected that this protein has lost its catalytic activity.