ANAPHYLACTIC RELEASE OF A BASOPHIL KALLIKREIN-LIKE ACTIVITY .1. PURIFICATION AND CHARACTERIZATION

These studies describe the IgE-mediated release of a basophil kallikrein-like enzyme that is an arginine esterase and is inhibited by plasma, diisopropylphosphofluoridate, and Trasylol. The substrate specificity for the synthetic amino acid ester substrates p-toluenesulfonyl-L-arginine methyl ester, benzoyl-arginine methyl ester and acetyl-tyrosine methyl ester is similar for the basophil enzyme and plasma kallikrein. The interaction of arginine esterase-active fractions from ion-exchange (DEAE-Sephacel) and gel filtration (Sepharose 6B) chromatography, with huma plasma kininogen, generates immunoreactive kinin. The basophil arginine esterase and kinin-generating activities co-cromatograph on Sepharose 6B and the quantity of kinin generated is, in general, proportional to the arginine esterase activity of the column fractions, suggesting that these two activities are subserved by the same protease. The ability of this protease to generate kinin equally well from heat- and acid-treated plasma, as from fresh human plasma, suggests that this protease has kallikrein-like activty. These data sugget that kallikrein-like actiivty can be generated from human basophils as a direct result of a primary IgE-mediated immune reaction, thus providing a potential link between reactions of immediate hypersensitivity and the plasma and (or) tissue kinin-generating systems.