The peptide in diet soft drinks
Aspartame
A sweetener made from two amino acids joined together. It's a dipeptide.
- Size
- 2 amino acids (a dipeptide)
- Made of
- Aspartic acid and phenylalanine
- Discovered
- December 1965
- Sweetness
- About 200 times sweeter than sugar
The story
In December 1965, chemist James Schlatter was working on an ulcer medicine at G.D. Searle, a drug company in the US. One step involved making a small dipeptide.
Some of it splashed onto his hand without him noticing. Later he licked his finger to pick up a piece of paper and tasted something intensely sweet. He'd washed his hands since breakfast, so he traced the taste back to the flask he'd been working with.
That accident became aspartame, now sold under names like NutraSweet and Equal.
Good to know
What makes aspartame surprising is that neither of its two amino acids tastes sweet on its own. Phenylalanine is actually bitter. Joined together in the right way, they become sweet.
It's a great example of how the order and shape of amino acids, not just which ones are used, decide what a peptide does.
Did you know?
Chemists later made the other three mirror-image versions of the same dipeptide. All three taste bitter, not sweet.