Isolation of human urinary kallikrein by affinity chromatography. Determination of human urinary kallikrein, I.

Human urinary kallikrein (EC 3.4.21.8) was purified to electrophoretically homogeneity by gel filtration on Sephadex G-100, followed by affinity chromatography on aprotinin-Sepharose. The molecular weight, estimated by gel filtration, is 64,000 Daltons, by dodecyl sulfate electrophoresis 45,000 Daltons and 29,000 Daltons, and it is microheterogeneous on electrofocusing, yielding isoelectric point values of 3.8, 3.9 and 4.05. The kinetic constants for hydrolysis of BZArgOEt, TosArgOMe, CbzTyrONp, and human HMW-kininogen were determined. Benzamidine and aprotinin are competitive inhibitors of human urinary kallikrein.