Abstract
The potencies of N-formylmethionyl (fMet) peptides as chemotactic agents for phagocytes are related to the rates at which they are hydrolyzed. Furthermore, chloromethyl ketones inhibit chemotaxis as do the products of hydrolysis of fMet peptides. The directed migration of cells in response to such peptides is probably brought about by the binding of the peptide to a cell receptor with subsequent cleavage by peptidase specific for aromatic residues, a process that allows the chemical gradient to be detected.