Research on sensing characteristics of three human umami receptors via receptor‐based biosensor

Abstract Currently, three proposed receptors, including heterodimer T1R1/T1R3, metabotropic glutamate receptor 4 (mGluR4) and metabotropic glutamate receptor 1 (mGluR1), are involved in mediating umami perception. The aim of this work was to study the sensing differences among three human umami receptors (T1R1, mGluR1 and mGluR4) without interference from other cellular signal pathways. The receptors were immobilized onto the precoated glassy carbon electrodes (GCE) to mimic cascade amplification system. The response currents towards monosodium glutamate (MSG) and disodium inosinate (IMP) were determined. The kinetic analyses showed that the allosteric constants of the interaction were as follows: K T1R1‐MSG = 7.183 × 10 −12 mol/L, K mGluR1‐MSG = 1.659 × 10 −14 mol/L, K mGluR4‐MSG = 7.610 × 10 −15 mol/L, K T1R1‐IMP = 7.810 × 10 −14 mol/L respectively. The results indicated that the sensing ability to MSG was as follows: mGluR4 > mGluR1 > T1R1. mGluRs might underly specific contribution to MSG recognition at lower concentration due to their specific structures and nerve connections. Summarily, this paper provided a novel establishment of receptor‐based biosensor, which would be useful for investigating mechanisms underlying umami signal transduction in vitro.