Putative taste receptor. TAS1R1/TAS1R3 responds to the umami taste stimulus (the taste of monosodium glutamate) (By similarity). Forms homodimers or a heterodimer with TAS1R1. Expressed in taste buds. Unlike most mammals domestic cats do not prefer and are unable to detect the sweetness of sugars. This is due to pseudogenization of the TAS1R2 gene which prevents the formation of the heterodimeric sweet taste receptor TAS1R2/TAS1R3. This molecular change was very likely an important event in the evolution of the cat's carnivorous behavior. Belongs to the G-protein coupled receptor 3 family. TAS1R subfamily.