Detergent solubilisation of the rabbit neutrophil receptor for chemotactic formyl peptides

Abstract

Digitonin was found to be the only detergent (out of 24 tested) capable of solubilizing the chemotactic formyl peptide receptor from rabbit neutrophil membranes in a form which retained its [3H]fMet-Leu-Phe binding activity. The solubilized material retained many of the characteristics of the membrane-bound receptor. [3H]fMet-Leu-Phe binding to the digitonin extract was measured at 4.degree. C using an equilibrium dialysis assay. Binding was saturable and of high affinity (Kd = 3.5 .+-. 0.7 nM). The potencies of a series of synthetic peptides as inhibitors of [3H]fMet-Leu-Phe binding to the soluble receptor showed the same rank order as for inhibition of the membrane-bound receptor. In addition, binding to both preparations was SH dependent showing a parallel inhibition by p-chloromercuribenzene sulphonate which could be partially reversed be subsequent incubation with dithiothreitol.