Calpain and kininogen mediated inflammation.

On the basis of previous findings that N-acetyl nonapeptide from the human calpain I large subunit has chemotactic activity for neutrophils, more than 30N-acetyl and unmodified peptides which have N-terminal amino acid sequences of the large and small subunits of calpains I and II were synthesized and their chemotactic activity was estimated. In addition to the above N-acetyl nonapeptide from the calpain I large subunit, an unmodified nonapeptide from the calpain II large subunit and several N-acetyl peptides of different lengths from the small subunit showed chemotactic activity. Furthermore, when calpain was incubated with either high molecular weight or low molecular weight kininogen, kinin liberation occurred with simultaneous inhibition of calpain by kininogen. These data suggest that chemical mediators generated from the calpain-kininogen system may participate in migration and accumulation of neutrophils to the inflammatory locus.