| Budget Amount *help |
¥22,880,000 (Direct Cost: ¥17,600,000、Indirect Cost: ¥5,280,000)
Fiscal Year 2010: ¥2,990,000 (Direct Cost: ¥2,300,000、Indirect Cost: ¥690,000)
Fiscal Year 2009: ¥8,190,000 (Direct Cost: ¥6,300,000、Indirect Cost: ¥1,890,000)
Fiscal Year 2008: ¥11,700,000 (Direct Cost: ¥9,000,000、Indirect Cost: ¥2,700,000)
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| Research Abstract |
Umami taste is elicited by L-glutamate, and is thought to be one of five basic taste qualities that plays a key role in intake of amino acids. A heterodimer of a G protein coupled receptor, T1R1 and T1R3, is proposed to function as its receptor. However, little is known about single nucleotide polymorphisms (SNP) in the genes and its potential links with individual differences in umami sensitivity. Here we investigated the association between recognition thresholds for umami substances and genetic variations in human T1R1 and T1R3, and the functions of T1R1/T1R3 variants using a heterologous expression system. Our study demonstrated that the T1R1-372Thr creates a more sensitive umami receptor than -372Ala, while T1R3-757Cys creates a less sensitive one than -757Arg for umami substances, and showed a strong correlation between the recognition thresholds and in vitro dose-response relationships. These results in human studies support the propositions that a T1R1/T1R3 heterodimer acts as an umami receptor, and that genetic variation in this heterodimer directly affects umami taste sensitivity.
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