Ide Nobuyuki, Sato Eriko, Ohta Keisuke, Masuda Tetsuya, Kitabatake Naofumi
Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Uji, Kyoto 611-0011, Japan.
J Agric Food Chem. 2009 Jul 8;57(13):5884-90. doi: 10.1021/jf803956f.
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.
本研究通过体外细胞实验和体内感官分析，对甜味蛋白奇异果甜蛋白和溶菌酶的甜度进行了研究，以阐明体外和体内反应特征之间的差异。构建了稳定表达人T1R2+T1R3甜味受体的Hek293细胞，并通过监测细胞内cAMP水平分析其对奇异果甜蛋白和溶菌酶的反应。结果表明，奇异果甜蛋白、溶菌酶以及阿斯巴甜均可导致转染T1R2+T1R3细胞内cAMP积累减少，且基于细胞实验测定的奇异果甜蛋白和溶菌酶的半数有效浓度（EC50）值与在140 mM NaCl存在下通过感官分析测定的甜度阈值结果高度一致。体外和体内实验结果均证实，甜味抑制剂乳糖唑可显著抑制奇异果甜蛋白和溶菌酶的甜度。
