What is "n-formylmethionine-leucyl-phenylalanine"

N-Formylmethionyl-leucyl-phenylalanine (FMLP) or N-formyl-met-leu-phe) is a N- formylated tripeptide and sometimes simply referred to as chemotactic peptide is a potent polymorphonuclear leukocyte (PMN) chemotactic factor and is also a macrophage activator.

FMLP is the prototypical representative of the N-fomylated oligopeptide family of chemotactic factors. These oligopeptides are known to be, or mimic the actions of, the N-formyl oligopeptides that are (a) released by tissue bacteria, (b) attract and activate circulating blood leukocytes by binding to specific G protein coupled receptors on these cells, and (c) thereby direct the inflammatory response to sites of bacterial invasion. FMLP is involved in the innate immunity mechanism for host defense against pathogens.

FMLP led to the first discovery of a leukocyte receptor for a chemotactic factor, defined three different types of FMLP receptors that have complimentary and/or opposing effects on inflammatory responses as well as many other activities, and helped define the stimulus-response coupling mechanisms by which diverse chemotactic factors and their G protein coupled receptors induce cellular function.