Identification of bitter ligands that specifically activate human t2r receptors and related assays for identifying human bitter taste modulators

An assay for identifying a compound which modulates a human T2R bitter taste receptor selected from hT2R1, hT2R3, hT2R4, hT2R5, hT2R7, hT2R8, hT2R9, hT2R10, hT2R13, hT2R14, hT2R16, hT2R44, hT2R44, hT2R50, hT2R54, hT2R55, hT2R61, hT2R64, hT2R65, hT2R67, hT2R71, hT2R75 and hT2R76 wherein said bitter taste receptor specifically responds to at least one bitter ligand selected from acesulfame K, acetaminophen, 2-acetyl pyrazine, aloin, amino-2-norbornane-carboxylic acid, amygdalin, andrographolide, arbutin, aristolochic acid, atropine, brucine, 4-benzylpiperidine, caffeine, chloramphenicol, chloroquine, cinchonine, ciprofloxacin, clarithromycin, clindamycin, cycloheximide, cyclooctanone, denatonium benzoate, dexamethasone, diltiazem hydrochloride, diisobutylamine, dimethylbiguanide, 2,6-dimethylpiperidine, doxepin, enalapril maleate, edrophonium, enoxacin, (−)-epicatechin, (−)-erythromycin, ethylpyrazine, famotidine, gabapentin, ginkgolide A, goitrin, guaiacol glyceryl ether, labetalol-HCl, linamarin, lomefloxacin, (−)-lupinine, N-methylthiourea, 1-methyl-2-quinolinone, methylprednisolone, nitrophthalene, nitrosaccharin, ofloxacin, oleuropein, omeprazole, oxybutynin chloride, oxyphenonium HBr, peptide-LPFNQL (SEQ ID NO:

• 51), peptide-LPFSQL (SEQ ID NO:
• 52), peptide-YQEPVLGPVRGPFPIIV (SEQ ID NO:
• 57), peptide-PVLGPVRGPFPIIV (SEQ ID NO:
• 58), peptide-PVRGPFPIIV (SEQ ID NO:
• 55), peptide-RGPFPIIV (SEQ ID NO:
• 56), N-ethyl-N′-phenylurea, 2-picoline, picric acid, pirenzepine dihydrochloride, phenylthiocarbamide, prednisone, procainamide, 6-n-propyl-2-thiouracil, quassin, quinacrine, quinine, ranitidine, saccharin, D-(−)-salicin, spartein sulfate pentahydrate, sucrose octaacetate, strychnine, sulfamethoxazole, theobromine, thioacetanilide, thiocarbanilide, tolazoline, tolylurea, trapidil, trimethoprim, and L-tryptophan which comprises:
• i. screening a compound for its effect on at least one of said bitter compounds to induce the activation of at least one of hT2R1, hT2R4, hT2R5, hT2R7, hT2R8, hT2R9, hT2R10, hT2R13, hT2R14, hT2R16, hT2R44, hT2R50, hT2R51, hT2R54, hT2R55, hT2R61, hT2R64, hT2R65, hT2R67, hT2R71, hT2R75, and hT2R76 polypeptides, wherein said hT2R polypeptide respectively (1) has the polypeptide sequence contained in SEQ ID NO:
• 4, 6, 8, 10, 12, 16, 18, 20, 22, 24, 26, 28, 32, 34, 36, 38, 40, 42, 44, 46, and 48, and/or (2) is encoded by a nucleic acid sequence contained in SEQ ID NO:3, 5, 7, 9, 11, 13, 17, 19, 21, 23, 25, 27, 31, 33, 35, 37, 39, 41, 43, 45 and 47 respectively, and/or (3) has a polypeptide sequence that possesses at least 90% sequence identity to of any of the polypeptides of SEQ ID NO:
• 4, 6, 8, 10, 12, 16, 18, 20, 22, 24, 26, 28, 32, 34, 36, 38, 40, 42, 44, 46, or 48, which polypeptide is activated by at least one of said bitter ligands, and ii. determining whether said compound modulates bitter taste based on its effect on the activation of said receptor by at least one of said bitter compounds;
• and iii. identifying said compound as a potential bitter taste modulator if it modulates the activation of said human bitter taste receptor by at least one of said bitter compounds.