In a Bind
Senomyx Inc. announced that the company's scientists have discovered that the human sweet taste receptor contains multiple binding sites for sweeteners and sweet taste inhibitors. A binding site for such sweet taste modulators was also identified in the related umami receptor, which mediates the savory taste of monosodium glutamate, or MSG. The company also announced that these results have been published in a manuscript authored by Senomyx employees Xu et al. and appeared online in the September 7 early edition of the Proceedings of the National Academy of Sciences. The manuscript by Xu et al. can be viewed at http://www.pnas.org/cgi/content/abstract/0404384101v1.
These discoveries, made by Senomyx senior scientists Xiaodong Li, Ph.D., Hong Xu, Ph.D. and coworkers, identify multiple binding sites on the human sweet taste receptor, a protein complex composed of T1R2 and T1R3 G protein-coupled receptors (GPCRs). Using cells engineered to express receptor chimeras, Li's team showed that sweeteners such as aspartame interact with the extracellular domain of T1R2. In contrast, sweeteners such as cyclamate and the sweet taste inhibitor lactisole interact with the transmembrane domain of T1R3. Additional studies described in the publication demonstrated that cyclamate and lactisole also interact with T1R3 of the umami, or savory, receptor, which is composed of T1R1 and T1R3.
"The work by Li and colleagues is being applied in our sweet enhancer and savory enhancer discovery and development programs," commented Mark Zoller, Ph.D., Senomyx's chief scientific officer and senior vice president of research. "A more detailed understanding of the biochemistry and structural features of the sweet and savory taste receptors provides important insights into the discovery and optimization of our enhancers," Zoller added.
"This discovery will enable us to further enhance our position as a leading company focused on using proprietary taste receptor-based assays to discover novel flavor enhancers and taste modulators for use in the packaged food and beverage industry," stated Kent Snyder, president and chief executive officer of Senomyx. Senomyx has entered into product discovery and development collaborations with four of the world's leading packaged food and beverage companies: Campbell Soup Company, The Coca-Cola Company, Kraft Foods Global Inc. and Nestle SA. "Our goal is to leverage our discovery and development capabilities by establishing additional collaborations with market-leading companies which are looking to improve the nutritional profile of their products by reducing the levels of carbohydrate sweeteners, salt or MSG," added Snyder.