QUANTITATIVE APPROACH FOR DETECTION AND CHARACTERIZATION OF FORMYL PEPTIDE RECEPTOR IN SOLUTION USING A PHOTOAFFINITY LIGAND

In this paper we describe an assay method for the rapid detection and quantitation of human neutrophil FMLP (N-formyl-methionyl-leucyl-pheny lalanine) receptor molecules. Although different assay methods are ava ilable to detect the receptor, none are rapid and at the same time all ow quantitative detection of the binding affinity of the receptor mole cule in solution. In our modified method, following a binding reaction using photoaffinity ligand, the amount of labeled ligand bound to the receptor is separated from the unbound one, thereby determining the b inding affinity of the receptor protein. This simple procedure not onl y makes it possible to detect the recombinant FMLP receptor protein ve ry rapidly, but also provides quantitative assessment of binding. This technique therefore allows a partial characterization (identification , determination of size and assessment of binding affinity) of recepto r molecule in solution in less than 24 hours.