Human Tissue kallikrein (HTK), a 42 kDa serine protease, cleaves kininogen to generate bioactive peptide kinin, which binds to its receptors and triggers a wide spectrum of biological functions.Kallikrein is purified from urine by ion-exchange radial flow membrane chromatography and aprotinin-conjugated affinity chromatography.The separation condition was optimized.Purified kallikrein was confirmed by SDS-PAGE followed by comassie staining, matrix-assisted laser desorption: ionization mass spectrometery (MALDI), kllikrein activity assay and specific HTK ELISA.Biological functions of kallikrein have been studied in various animal models.