A photoaffinity probe for 5-hydroxyeicosanoid dehydrogenase suitable for radioiodination

5-Hydroxy eicosanoid dehydrogenase (5h-dh) is a key enzyme responsible for the biosynthesis of 5-oxo-ETE, a potent eosinophil chemoattractant. To facilitate the identification and characterization of 5h-dh we have synthesized a photoaffinity ligand 7, designed to bind to the enzyme, and shown it to be an excellent substrate for 5h-dh. We have also synthesized a precursor 34, containing the photoaffinity label and a trimethyl tin group that can readily be displaced by iodide and will be suitable for radioiodination with 125I.