title: Interactions of the sweet-tasting proteins thaumatin and lysozyme with the human sweet-taste receptor.
abstract: This study investigated the sweetness of the sweet-tasting protein thaumatin and lysozyme by both an in vitro cell-based assay and an in vivo sensory analysis to elucidate the differences between in vitro and in vivo response profiles. Hek293 cells were constructed that stably expressed the human T1R2+T1R3 sweet-taste receptor, and their responses to thaumatin and lysozyme were analyzed by monitoring the levels of intracellular cAMP. The results indicated that thaumatin and lysozyme as well as aspartame induced a decrease in the intracellular cAMP accumulation of the T1R2+T1R3-transfected cells and that EC(50) values of thaumatin and lysozyme determined by cell-based assay are well-consistent with the results of the sweetness threshold value determined by sensory analysis in the presence of 140 mM NaCl. The results of both in vitro and in vivo experiments confirmed that the sweetness inhibitor lactisole significantly suppressed the sweetness of thaumatin and lysozyme.
authors.affiliation: Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Uji, Kyoto 611-0011, Japan.
authors.forename: Nobuyuki
authors.initials: N
authors.lastname: Ide
authors.forename: Eriko
authors.initials: E
authors.lastname: Sato
authors.forename: Keisuke
authors.initials: K
authors.lastname: Ohta
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Masuda
authors.forename: Naofumi
authors.initials: N
authors.lastname: Kitabatake
mesh_terms: D001555:Benzene Derivatives / Q000494:pharmacology; D002460:Cell Line; D003001:Cloning, Molecular; D000242:Cyclic AMP / Q000032:analysis; D015870:Gene Expression; D006801:Humans; D007668:Kidney; D009113:Muramidase / Q000494:pharmacology*; D010940:Plant Proteins / Q000494:pharmacology*; D043562:Receptors, G-Protein-Coupled / Q000187:drug effects* / Q000235:genetics / Q000502:physiology; D012965:Sodium Chloride / Q000494:pharmacology; D013549:Sweetening Agents / Q000494:pharmacology; D014162:Transfection
chemical_list: D001555:Benzene Derivatives; D010940:Plant Proteins; D043562:Receptors, G-Protein-Coupled; D013549:Sweetening Agents; C431926:taste receptors, type 1; D012965:Sodium Chloride; C003427:thaumatin protein, plant; D000242:Cyclic AMP; D009113:Muramidase; C495512:lactisole