Scientists in the US have recently demonstrated the function of both a human receptor that responds to sweeteners and a related human receptor that responds to glutamate, a savoury tasting molecule found in a variety of meats, cheeses and vegetables and associated with the umami taste. They predict that the new discoveries could lead to new alternatives to monosodium glutamate.
Researchers from the company Senomyx described their results in a paper published in the 2 April issue of the Proceedings of the National Academy of Sciences and will present the results at the annual meeting of the Association for Chemoreception Sciences beginning on 24 April 2002 in Sarasota, Florida.
Elliot Adler and Senomyx colleagues Xiaodong Li, Lena Staszewski and Hong Xu, described the function of a family of human proteins that are encoded by three T1R genes. Using cells engineered to express combinations of the human T1R genes, Dr Adler's team showed that human T1R2 and T1R3 combine to form a receptor that responds to a wide variety of both natural and synthetic sweeteners and that human T1R1 and T1R3 combine to form a receptor that responds to monosodium glutamate (MSG) and other umami taste substances.
Dr Adler found that the human umami receptor, in contrast with the orthologous rodent receptor, is highly tuned for glutamate compared to other amino acids.
The discoveries on the human sweet and umami receptors have accelerated two major discovery programmes at Senomyx. "A key element of our discovery process is the use of human taste and smell receptors in functional assays to screen for novel receptor activators and blockers,'' said Mark Zoller, Senomyx's chief scientific officer and senior vice president of research. "The work by Dr Adler and his team enables Senomyx to initiate high-throughput screening and potentially discover alternatives to MSG, as well as enhancers of sweet and umami tastes. Such taste modulators could improve the healthfulness and taste of foods, and such taste modulators would otherwise be extremely difficult to discover without having the human taste receptors in hand,'' continued Dr Zoller.
The company reports that the research results on human sweet and umami taste receptors have also expanded the company's business opportunities. "Senomyx was established to discover novel molecules that modulate taste and smell for application in consumer products. These new discoveries have created two broad new areas for product development collaborations,'' said Paul A. Grayson, chief executive officer, Senomyx.