Allosteric ligands for sweet and umami taste receptors
Taste enhancers stabilize either the active form of the VFTM or that of the 7-TM region by binding to allosteric sites. Lactisole is an allosteric antagonist at both taste receptors. See section II.B for further details.
Compound
Structure
Potencies
Comments
References
Cyclamate
EC50 = 3 mM
Allosteric agonist (sweet) or modulator (umami) binding to the 7TM domain of T1R3
Xu et al., 2004; Jiang et al., 2005b
Lactisole
IC50 = 41 μM
Negative modulator binding to the 7TM domain of T1R3 (sweet/umami)
Xu et al., 2004; Jiang et al., 2005a
S807
EC50 ≈ 0.5 μM
Allosteric agonist binding to the 7TM domain of T1R1 (umami)
Zhang et al., 2008a
S819
Allosteric agonist binding to the 7TM domain of T1R2 (sweet)
Zhang et al., 2008a
IMP
EC50 ≈ 3 mM
Naturally occurring umami taste enhancer stabilizing the closed conformation of the T1R1-VFTM (Fig. 6)
Li et al., 2002; Nelson et al., 2002; Zhang et al., 2008a
SE-2
EC50 = 22 μM
Positive modulators of the sweet receptor, stabilizing the closed form of the T1R2-VFTM