Some properties of human pancreatic kallikrein and comparison with human trypsins and porcine kallikrein.

The properties of human pancreatic kallikrein purified from pancreatic juice were investigated. The enzyme is very stable at pH 8 but is rapidly inactivated at pH 2.6. It is a glycoprotein with a molecular weight of 35 000 as determined by gel filtration on Sephadex G-200. Contrary to the two human trypsins, human kallikrein like porcine pancreatic kallikrein is unable to hydrolyse casein and Met-Lys-bradykinin. Human pancreatic kallikrein is inactivated by diisopropyl fluorophosphate but not by chloro (N-p-toluolsulfonly-L-lysyl)methane. The enzyme does not react with various proteinase inhibitors (secretory pancreatic trypsin inhibitors, ovomucoid, lima bean and soybean trypsin inhibitors) but is inhibited by the Kunitz pancreatic trypsin inhibitor.