Identification of Serotonin-Binding Proteins Using a Photoaffinity Labeling Probe
Two types of serotonin-binding proteins from rat hypothalamus and spinal cord have been isolated and purified in our laboratory.1 Antibodies to both types of purified serotonin-binding proteins were obtained, and their interactions with LSD were studied2. Unfortunately, the low yield of purified serotonin-binding proteins prevented thorough biochemical characterizations. We are now reporting a new approach to the study of serotonin-binding proteins. An arylazide derivative of ssr tonin has been synthesized as a photoaffinity labeling probe.3,4 This derivative, [3H]-nitroarylazidophenyl-serotonin ([3 H]-NAP-serotonin), binds to protein components of brain homogenates and upon irradiation becomes covalently attached to protein through an active nitrene group. The radioactively labeled proteins can then be separated by sodium dodecyl sulfate (SDS) polyacrylamide gel electrophoresis5. This technique provides more specific information than do conventional radioligand binding assays with membrane preparations because the covalent binding of the photoaffinity labeling probe allows individual serotonin-binding proteins to be identified.
KeywordsCovalent Binding Radioligand Binding Assay Lysergic Acid Serotonin Binding Postsynaptic Serotonin
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