Glandular kallikreins cleave Met-Lys and Arg-Ser bonds in kininogen to release Lys-bradykinin. Displays trypsin-like substrate specificity and shows activity towards casein, gelatin, fibronectin and IGFBP3. Preferential cleavage of Arg-|-Xaa bonds in small molecule substrates. Highly selective action to release kallidin (lysyl-bradykinin) from kininogen involves hydrolysis of Met-|-Xaa or Leu-|-Xaa. Inhibited by protease inhibitors diisopropylfluorophosphate, leupeptin, antipain, benzamidine, phenylmethylsulfonyl fluoride and soybean trypsin inhibitor. Expressed in testis and submaxillary gland. In the testis, expression localized specifically to Leydig cells in the interstitial tissues. Detectable in testis 4 weeks after birth, becoming more prominent thereafter. By T protein. Belongs to the peptidase S1 family. Kallikrein subfamily.