Characteristics of binding of a potent chemotactic formyl tetrapeptide, formylmethionyl-leucyl-phenylalanyl-phenylalanine, to the receptors on rabbit neutrophils.
Binding of a potent chemotactic formyl tetrapeptide, formylmethionyl-leucyl-phenylalanyl-phenylalanine (fMet-Leu-Phe-Phe), to the formyl peptide receptors on the rabbit neutrophil was assessed by two approaches. A tritiated preparation of fMet-Leu-Phe-Phe was used for direct binding studies, whereas indirect studies comprised an assessment of the ability of the formyl tetrapeptide to competitively inhibit the binding of 35S-labeled formylmethionyl-leucyl-phenylalanine. These two approaches yielded analogous results. The formyl tetrapeptide fMet-Leu-Phe-Phe showed rapid and saturable binding to the same chemotactic receptors as the less potent formyl tripeptides with which it was compared. Its equilibrium-binding pattern, however, was different: fMet-Leu-Phe-Phe showed a homogeneous binding pattern, in contrast to the heterogeneity seen with the less potent compounds. The relative potencies for high-affinity binding of the two standard formyl tripeptides and fMet-Leu-Phe-Phe correlated well with their relative potencies for stimulating the biological response of degranulation; the relative potencies for low-affinity binding correlated less well.
Kermode
J C
JC
Department of Pathology, University of Connecticut Health Center, Farmington.
Muthukumaraswamy
N
N
Freer
R J
RJ
D000818:Animals; D001667:Binding, Competitive; D002630:Chemotactic Factors / Q000378:metabolism*; D009240:N-Formylmethionine Leucyl-Phenylalanine / Q000031:analogs & derivatives* / Q000378:metabolism; D009504:Neutrophils / Q000378:metabolism*; D009842:Oligopeptides / Q000378:metabolism; D011817:Rabbits; D044042:Receptors, Formyl Peptide; D011971:Receptors, Immunologic / Q000378:metabolism*; D013997:Time Factors
D002630:Chemotactic Factors; D009842:Oligopeptides; D044042:Receptors, Formyl Peptide; D011971:Receptors, Immunologic; D009240:N-Formylmethionine Leucyl-Phenylalanine; C024998:N-formylnorleucyl-leucyl-4-phenylalanine; C055978:N-formyl-methionyl-leucyl-phenylalanyl-phenylalanine