Sweet Taste in Man: A Review

Abstract

A greater understanding of the molecular mechanisms of sweet taste has profound significance for the food industry as well as for consumers. Understanding the mechanism by which sweet taste is elicited by saccharides, peptides, and proteins will assist science and industry in their search for sweet substances with fewer negative health effects. The original AH-B theories have been supplanted by detailed structural models. Recent identification of the human sweet receptor as a dimeric G-protein coupled receptor comprising T1R2 and T1R3 subunits has greatly increased the understanding of the mechanisms involved in sweet molecule binding and sweet taste transduction. This review discusses early theories of the sweet receptor, recent research of sweetener chemoreception of nonprotein and protein ligands, homology modeling, the transduction pathway, the possibility of the sweet receptor functioning allosterically, as well as the implications of allelic variation.

Position of the Academy of Nutrition and Dietetics: Use of Nutritive and Nonnutritive Sweeteners

“…Taste receptor cells are organized into taste buds, which are distributed throughout the tongue and on specialized structures called papillae (4). Sweet taste is elicited through interaction with a sweet receptor, identified as a dimeric G-protein coupled receptor composed of T1R2 and T1R3 subunits with multiple active sites (5). Li and colleagues (6) showed that these receptors (T1R2 and T1R3) responded to sugars (ie, sucrose, fructose, galactose, glucose, lactose, and maltose), amino acids (ie, glycine and D-tryptophan), sweet proteins (ie, monellin and thaumatin), and NNS (ie, acesulfame K, aspartame, cyclamate, dulcin, neotame, saccharin, and sucralose), although specific preferential binding sites may vary.…”

Enhanced Expression of the Sweet Taste Receptors and Alpha-gustducin in Reactive Astrocytes of the Rat Hippocampus Following Ischemic Injury

“…The heterodimer of T1R2 and T1R3 proteins is a broadly acting sweet taste receptor that acts through a-gustducin, a transducin-like G protein a-subunit, to activate adenylyl cyclase leading to an increase in cyclic adenosine 3 0 ,5 0 -monophosphate (cAMP), or which acts through the bc-subunit of gustducin to activate a phospholipase Cb2-dependent pathway (for review, see [1][2][3]). In addition to the taste receptor cells in the tongue, the sweet taste receptor is expressed in enteroendocrine and pancreatic b cells and has been proposed to be associated with the regulation of glucose absorption and enteroendocrine hormone secretion [4][5][6][7][8].…”

Sweetness Sensor with Lipid/Polymer Membranes: Response to Various Sugars

“…(9) Such studies on structure-activity relationships (SAR) have been widely carried out until, finally, the sweet taste receptor was identified in the early 2,000s. (10) It is becoming clear that only a single sweet taste receptor responds to almost all sweet-tasting substances, including sweet proteins, sweet amino acids, and high-potency sweeteners, as well as sugars. (10) As far as sugars as sweet-tasting molecules are concerned, the only evidence of sweet taste receptor binding sites was reported by Nie et al, demonstrating that sucrose and glucose bind to the N-terminal domain of its two subunits (T1R2 and T1R3) with different affinities; sucrose binds more readily to the T1R3 subunit whereas glucose binds more readily to the T1R2 subunit.…”

“…(10) It is becoming clear that only a single sweet taste receptor responds to almost all sweet-tasting substances, including sweet proteins, sweet amino acids, and high-potency sweeteners, as well as sugars. (10) As far as sugars as sweet-tasting molecules are concerned, the only evidence of sweet taste receptor binding sites was reported by Nie et al, demonstrating that sucrose and glucose bind to the N-terminal domain of its two subunits (T1R2 and T1R3) with different affinities; sucrose binds more readily to the T1R3 subunit whereas glucose binds more readily to the T1R2 subunit. (11) In any case, sweet-tasting sugars have hydroxyl groups, which appear to play important role(s) in the interaction with the human receptor.…”