Amino acids are the building blocks of proteins, and thus are important both as nutrients and as fuel - the ability to taste them is probably of evolutionary importance.
Charles Zuker of the University of California, San Diego, USA, and colleagues believe that the receptor they have discovered, called T1R1+3, is part of the response to 'umami' flavors - the lip-smacking quality possessed by monosodium glutamate.
Receptors for sweet and bitter flavors have already been identified.
|T1R1+3 is a receptor that responds to the taste of amino acids. |
Although T1R1+3 responds to most of the naturally occurring amino acids, the perception of these chemicals can differ from sweet to bitter.
The researchers also found that the genes for T1R1 and T1R3, the two halves of the new receptor, vary between and within mice and humans, probably causing differences in the sense of taste.