Sweetness in Fine Detail

The subunits of the sweet taste receptor have distinct affinities for different saccharides, according to a new study. The finding could help with the design of better synthetic sweeteners. The sweet taste receptor is made of two subunits, T1R2 and T1R3. Although it has been known that the nonsaccharide sweetener aspartame binds only to T1R2 and cyclamate only to T1R3, which subunit interacts with saccharides was not known until now. The study by Graeme L. Conn, of the University of Manchester, in England; Steven D. Munger, of the University of Maryland School of Medicine, Baltimore; and coworkers indicates that both T1R2 and T1R3 bind saccharides with different affinities (Curr. Biol. 2005, 15, 1948). The study shows that sucrose and the low-calorie sweetener sucralose (shown) interact with both subunits. Furthermore, sucralose binds with either subunit with greater affinity than does sucrose.