LIFE SCIENCES, vol.48, no.18, pp.1757-1762, 1991 (SCI-Expanded)
We prepared a tritiated chloromethyl ketone derivative of Tyr-D-Ala-Gly(Me)Phe-Gly-ol H-3-D-Ala-Gly-(Me)Phe-chloromethyl ketone, and studied its binding characteristics in rat brain membranes. A significant portion (about 70%) of the binding becomes wash-resistant after 60 min of incubation. The binding of the ligand is highly stereospecific and mu-opioid receptor selective. These characteristics of the ligand, together with its high specific radioactivity (57 Ci/mmol) makes it a good candidate for biochemical characterization and covalent labeling of mu opioid receptors.