Isolation of an enzymatically active glandular kallikrein from human plasma by immunoaffinity chromatography

A glandular kallikrein from human plasma was isolated by immunoaffinity chromatography and characterized. The molecular weight was determined to 40,000 by gel filtration. The enzyme preparation liberates kinins from human HMW kininogen (specific activity: 0.328 HMW kininogen-U/A280 unit), lowers the blood pressure of dogs after intravenous injection (specific activity: 1090 KE/A280 unit), is inhibited by diisopropyl fluorophosphate and aprotinin, but not by SBTI. In the radioimmunoassay for human urinary kallikrein parallel binding curves were obtained. AcPheArgOEt, DVal-LeuArgOEt and ZTyrONp are cleaved with identical rates by the kallikrein preparation and human urinary kallikrein.