Question

The standard free energy change (\(\Delta G^0\)) of the binding reaction between different sweet molecules and a common sweet taste receptor are given. Which amongst these molecules is the sweetest at the same molar concentration?

• A. Sucrose (-6.7 kcal mol\(^{-1}\))
• B. Saccharin (-9.7 kcal mol\(^{-1}\))
• C. Alitame (-11.1 kcal mol\(^{-1}\))
• D. Neotame (-12.1 kcal mol\(^{-1}\))

Hint:

More negative \(\Delta G^0\) \(\Rightarrow\) higher binding affinity \(\Rightarrow\) sweeter taste.

Answer 1

The Correct Option is D

Step 1: Recall principle.
The sweeter the molecule, the stronger its binding affinity to the sweet receptor. Stronger binding corresponds to more negative \(\Delta G^0\).
Step 2: Compare values.
- Sucrose: -6.7 kcal/mol (least negative).
- Saccharin: -9.7 kcal/mol.
- Alitame: -11.1 kcal/mol.
- Neotame: -12.1 kcal/mol (most negative, strongest binding).
Step 3: Conclusion.
Thus, Neotame is the sweetest molecule at the same molar concentration.
Final Answer: \[ \boxed{\text{Neotame (-12.1 kcal mol}^{-1}\text{) is the sweetest.}} \]