A chloride-activated aminopeptidase in rat inflammatory exudate: Properties and evidence of the origin of the enzyme

Abstract The activity levels of a chloride-dependent arginine aminopeptidase in an inflammatory exudate collected from sponges implanted in the dorsal region of rats, was found to be connected to the number of leukocytes present. Leukopenia caused a corresponding decrease in the exudate enzyme activity. Disruption of the cells by injecting Triton X-100 into the sponges in vivo immediately increased the enzyme activity levels. The enzyme was activated by NaCl; the maximum rate of hydrolysis was measured at 0.2 M NaCl. The enzyme was activated by thiols and strongly inhibited by 10 −6 M p -chloromercuribenzoate. The isoelectric point of the enzyme was at pH 5.1. The properties of the enzyme support the idea of its similarity with an arginine aminopeptidase demonstrated earlier in various inflammatory processes.