title: Biochemical studies of taste sensation--XII. Specificity of binding of taste ligands to a sedimentable fraction from catfish taste tissue.
abstract: The specificity of amino acid binding sites in a sedimentable fraction prepared from catfish taste epithelium was examined. Using seven 3H-labeled amino acids as ligands and the unlabeled amino acids in binding competition assays, the presence of possibly three classes of amino acid binding sites was deduced. Site 1 binds L-THR, L-SER, L-ALA and possibly D-ALA and beta-ALA, Site 2 binds L-SER, L-ALA, GLY, D-ALA, and beta-ALA and Site 3 binds L-ARG and L-LYS. Additional evidence supporting the specificity of Site 2 was obtained from the specificity of enhancement of L-ALA binding. The results demonstrate the presence of some major classes of taste receptor sites, and provide a basis for understanding taste receptor specificity at the biochemical level.
mesh_terms: D000596:Amino Acids / Q000378:metabolism; D000818:Animals; D001667:Binding, Competitive; D004848:Epithelium / Q000502:physiology; D008024:Ligands; D013649:Taste / Q000502:physiology*; D013650:Taste Buds / Q000502:physiology*
chemical_list: D000596:Amino Acids; D008024:Ligands