TAS2R1

TAS2R1 is one of the human bitter taste receptor subtypes. In a 2008 study by Maehashi and colleagues using calcium imaging in HEK293 cells stably expressing hTAS2R1, the bitter dipeptides Gly-Phe and Gly-Leu (25 mM) were shown to strongly activate hTAS2R1, whereas the tasteless dipeptide Gly-Gly did not activate any of the receptors even when tested up to 100 mM.

In a 2010 study using C6 glioma cells by Upadhyaya and colleagues (confirmed from the abstract scope), bitter tripeptides were reported to activate T2R1 more strongly than dipeptides, and the EC50 of Phe-Phe-Phe (FFF), which showed the strongest activity, was in the micromolar range. Homology modeling suggested that these bitter peptides bind to a common binding site on the extracellular face of the receptor.

In 2025, a study that integrated receptor-activation, sensory, and sequence data on bitter peptides identified TAS2R1 as the receptor among those activated by bitter peptides that showed activation by the largest variety of peptide types. The list from this study includes numerous amino acids and peptides—such as Phe (F), Gly-Phe (GF), Gly-Leu (GL), and Phe-Phe-Phe (FFF)—that are recorded as activating TAS2R1.

In receptor assays using bile acids as candidates, TAS2R1 was activated by cholic acid at 100 µM and taurocholic acid at 100 µM, whereas it responded to lithocholic acid at a lower concentration of 0.3 µM. Among the bile acids examined in that study, lithocholic acid and its taurine conjugate were ranked among the most potent.

In a receptor screening of oligomers isolated from the mushroom Amaropostia stiptca, oligomers A, B, D, and E all activated TAS2R1 at a threshold concentration of 30 µM, whereas oligomer F showed no activation. Separately, a review notes that larger peptides arising during the cheese-maturation process also activate TAS2R1.