title: Photoaffinity labeling of thaumatin-binding protein in monkey circumvallate papillae.
abstract: Thaumatin I is an intensely sweet-tasting protein. It was photo-crosslinked with taste papillae of crab-eating monkey by using a conjugated photo-affinity reagent [3H]azidobenzoylthaumatin I. Serial sections of SDS-polyacrylamide gel electrophoresis of the 0.1 M sodium phosphate buffer-soluble fraction from taste papillae had a large peak of radioactivity at the Mr region of approx. 70,000; fractions from non-taste papillae did not. Excess unlabeled thaumatin I reduced the photo-crosslinking at the 70 kDa region; acetylated thaumatin I (which is not sweet) did not. The results show that taste papillae of the monkey contain a protein of Mr approx. 50,000, which binds to thaumatin I (Mr 22,209) but not to completely acetylated thaumatin I. The possibility that the thaumatin-binding protein is a sweet receptor protein is discussed.
mesh_terms: D000107:Acetylation; D000345:Affinity Labels / Q000138:chemical synthesis; D000818:Animals; D001345:Autoradiography; D001386:Azides / Q000138:chemical synthesis; D002352:Carrier Proteins / Q000032:analysis*; D003432:Cross-Linking Reagents; D004591:Electrophoresis, Polyacrylamide Gel; D047908:Intracellular Signaling Peptides and Proteins; D008252:Macaca fascicularis; D010710:Phosphates / Q000494:pharmacology; D010777:Photochemistry; D010940:Plant Proteins / Q000302:isolation & purification; D011506:Proteins; D012965:Sodium Chloride / Q000494:pharmacology; D013549:Sweetening Agents / Q000494:pharmacology; D013650:Taste Buds / Q000378:metabolism*
chemical_list: C050729:4-azidobenzoyl-thaumatin I; D000345:Affinity Labels; D001386:Azides; D002352:Carrier Proteins; D003432:Cross-Linking Reagents; D047908:Intracellular Signaling Peptides and Proteins; D010710:Phosphates; D010940:Plant Proteins; D011506:Proteins; D013549:Sweetening Agents; C050728:thaumatin-binding protein, monkey; D012965:Sodium Chloride; C003427:thaumatin protein, plant