New synthetic substrate for kallikrein and its application.

We developed a new synthetic substrate, Pro-Phe-Arg-alpha-naphthyl ester, for kallikrein. We found that this substrate had higher specificity and sensitivity for kallikrein and was applied for the preparation of zymogram and for the histochemical demonstration. With Pro-Phe-Arg-alpha-NE as substrate, the minimum detectable concentration of human urinary kallikrein was about 0.001 KU and then kallikrein could be determined with 25 microliter of human urine. We also found the possibility that occurring of abnormalities during pregnancy were predicted by the determination of urinary kallikrein of pregnants. Zymograms were prepared for various kinds of kallikrein using this substrate. The localization of kallikrein-like enzyme in rat kidneys was defined by the application this substrate for histochemistry. Moreover, cytochemical demonstrations of leucocytes in human blood were done using Ts-Lys-alpha-NE and Ac-Tyr-alpha-NE.