The present invention is intended to provide a specific antibody to a protein that does not have a known protein motif structure but has proteolytic activity and regulating action on the activity of other proteases, cell invasiveness and smooth muscle contraction and relaxation, and is capable of treating, preventing and diagnosing various diseases. The protein is for the treatment, prevention or diagnosis of a disease selected from the group consisting of perinatal diseases, infertility, cancer, nervous system diseases, inflammatory diseases, immune diseases, cardiovascular diseases, endocrine diseases, viral infections, bacterial infections and prion diseases, and is shown in Sequence listing 1.