Rat stomach kallikrein: its purification and properties

From rat stomach, kallikrein was purified by chromatographies on columns of p-aminobenzamidine-Sepharose, DEAE-Sephadex A-50 and Sephadex G-150 and by isoelectric focusing, measuring its activities to hydrolyse prolylphenylalanyl-arginine-4-methyl-coumarine amide (Pro-Phe-Arg-MCA) and to release kinin from rat heated-plasma. The purified stomach kallikrein showed a single band on Disc electrophoresis at pH 7.0. The molecular weight of the kallikrein was calculated to be 29,000 by gel-filtration on a column of Sephadex G-50. The kallikrein was stable between pH 6 and 11 and hydrolysed Pro-Phe-Arg-MCA optimally at pH 11.0. The Pro-Phe-Arg-MCA hydrolysing activity of rat stomach kallikrein was inhibited by DFP and Trasylol, but not by trypsin inhibitors from soyabean, limabean and ovomucoid. These properties of rat stomach kallikrein was clearly distinguishable from those of partially purified rat plasma kallikrein, but similar properties to other glandular kallikreins from other species. From these results, it was concluded that kallikrein is present in rat stomach, which can be classified into glandular kallikrein.