EFFECT OF SOME PROTEASE SUBSTRATES AND INHIBITORS ON CHEMOTAXIS AND PROTEASE ACTIVITY OF HUMAN POLYMORPHONUCLEAR LEUKOCYTES

Both low- and high-molecular-weight inhibitors of serine proteases were found to inhibit chemotaxis by human polymorphonuclear leukocytes totally at widely varying concentrations. Synthetic low-molecular-weight substrates with trypsin-like or chymotryp- sin-like specificity were also shown to be potent inhibitors of chemotaxis. Chemotactic inhibition was reversible except with a titrant for the active site of a serine protease. N-acetyl-L-tyrosine ethyl ester was found to be a suitable substrate for measuring protease activity of polymorphonuclear leukocytes. Concentrations of the various protease inhibitors that caused 100% chemotactic inhibition caused 80%-100% inhibition of protease activity of polymorphonuclear leukocytes. © 1979 by The University of Chicago.