Release of the chloride-dependent arginine aminopeptidase from PMN leukocytes and macrophaces during phagocytosis

Abstract

The zymosan particles induced a time-dependent release of the chloride-dependent arginine aminopeptidase from rat peritoneal macrophages during in vitro incubations. Intraperitoneal injections of zymosan, a streptococcal cell preparation and a Micrococcu -suspension caused the release of the chloride-activated arginine aminopeptidase into the peritoneal fluid. The arginine aminopeptidases obtained both from the cell cultivation media and the peritoneal washes were partly purified. The enzymes were similar with regard to the following properties: chloride activation with an optimum at physiological concentrations; strong inhibition by 10 −6M p -chloromercuribenzoate; similar elution properties and preferential hydrolysis of mainly the N -L-aminoacyl-2-naphthylamines of arginine and lysine. The chloride-activated arginine aminopeptidase released into the media in in vitro conditions was inactivated in contrast to the enzyme released into the peritoneal fluid as a result of the intraperitoneal injections. The timing of the release of the chloride-activated arginine aminopeptidase both in and in vitro suggests that the enzyme plays a role in the initial phases of inflammation.