Biochemistry and functional aspects of human glandular kallikreins

Abstract

Human urinary kallikrein was purified by gel filtration on Sephacryl S-200 and affinity chromatography on aprotlnin-Sepharose, followed by ion exchange chromatography on DEAE-Sepharose. In dodeeylsulfate gel electrophoresis two protein bands with molecular weights of 41,000 and 34,000 were separated. The amino acid composition and the carbohydrate content of the kalllkrein preparation were determined; isoleuelne was identified as the only aminoterminal amino acid. The bimolecular veloeity constant for the inhibition by dilsopropyl fluorophosphate was determined as 9 +2 I tool -1 min -1. The hydrolysis of a number of substrates was investigated and AePheArgOEt was found to be the most sensitive substrate for human urinary kallikrein. Using this substrate an assay method for kallikrein in human urine was developed.It was shown by radiolmmunoassay that pig pancreatic kallikrein can be absorbed in the rat intestinal tract. Furthermore, in dogs the renal excretion of glandular kallikrein from blood was demonstrated by radioimmunological methods.