Before You Begin
Question #44955
The Question
A pure sample of the protected tripeptide \ce{N-acetyl-L-threonyl-L-isoleucyl-L-valinamide} is dissolved in an aqueous buffer at and heated at for an extended period. This leads to complete thermodynamic equilibration via base-catalyzed proton abstraction of all susceptible carbon atoms. Assuming no peptide bond cleavage, elimination reactions, or side-chain degradation occurs, what is the total number of stereoisomers of this molecule present in the final equilibrium mixture?
Options
- A.
8
- B.
16
- C.
32
- D.
4
Check Your Answer
Correct Answer
Step-by-Step Solution
Explanation
How the Examiner Thinks
Exception_Exposure
Learn to identify edge cases and boundary exceptions that JEE examiners hide in math problems.
Concepts Behind This Question
Epimerization vs Anomerization|Amino Acid Zwitterion pH Sensitivity|Peptide Bond Planarity
Why This Question Is Tricky
Common Mistakes
The question tests the student's ability to identify susceptible enolizable stereocenters in a complex biomolecule under basic conditions.
A common trap is assuming that all chiral centers in a molecule will epimerize under harsh conditions (yielding 32), or failing to recognize that amino acids like Threonine and Isoleucine possess a second, non-enolizable chiral center at the -position.
This effectively differentiates between the base-catalyzed enolization mechanism (epimerization) and general stereochemical inversion, reinforcing the structural requirements for carbanion/enolate stability.
Quick Facts About This Question
Question Information
| Subject | Chemistry |
| Chapter | Biomolecules - Class 12 |
| Concept | Epimerization vs Anomerization |
| Difficulty | 8 |
| Cognitive Load | 7 |
| Target Solve Time | 160 sec |
| Access | Free |