Kallikrein-13 (KLK13) is also known as Kallikrein-like protein 4 (KLK-L4), is a secreted protein, belongs to the peptidase S1 family and Kallikrein subfamily. KLK-13 contains one peptidase S1 domain. KLK13 is mainly expressed in prostate, breast, testis and salivary gland. KLK13 may be involved in the pathogenesis and / or progression of breast and ovary cancers, and is regarded as a novel cancer biomarker. In addition, KLK13 interacts and forms complexes with several serum protease inhibitors, such as alpha2-macroglobulin, and its expression is regulated by steroid hormones. This protein is fused with 6xhis tag at the C-terminus, and has a calculated MW of 28 kDa. The predicted N-terminus is Gly 18. DTT-reduced Protein migrates as 33-40 kD