Table of contents

1. A Review of General Chemistry5h 5m
2. Molecular Representations1h 14m
3. Acids and Bases2h 46m
4. Alkanes and Cycloalkanes4h 17m
5. Chirality3h 39m
6. Thermodynamics and Kinetics1h 22m
7. Substitution Reactions1h 48m
8. Elimination Reactions2h 30m
9. Alkenes and Alkynes2h 9m
10. Addition Reactions3h 19m
11. Radical Reactions1h 58m
12. Alcohols, Ethers, Epoxides and Thiols2h 42m
13. Alcohols and Carbonyl Compounds2h 17m
14. Synthetic Techniques1h 26m
15. Analytical Techniques:IR, NMR, Mass Spect7h 3m
16. Conjugated Systems6h 13m
17. Ultraviolet Spectroscopy51m
18. Aromaticity2h 34m
19. Reactions of Aromatics: EAS and Beyond5h 1m
20. Phenols55m
21. Aldehydes and Ketones: Nucleophilic Addition4h 56m
22. Carboxylic Acid Derivatives: NAS2h 51m
23. The Chemistry of Thioesters, Phophate Ester and Phosphate Anhydrides1h 10m
24. Enolate Chemistry: Reactions at the Alpha-Carbon1h 53m
25. Condensation Chemistry2h 9m
26. Amines1h 43m
27. Heterocycles2h 0m
28. Carbohydrates5h 53m
29. Amino Acids4h 20m
30. Peptides and Proteins2h 42m
31. Catalysis in Organic Reactions1h 30m
32. Lipids 2h 50m
33. The Organic Chemistry of Metabolic Pathways2h 52m
34. Nucleic Acids1h 32m
35. Transition Metals6h 14m
36. Synthetic Polymers1h 49m

16. Conjugated Systems

Photochemical Electrocyclic Reactions

Organic Chemistry

16. Conjugated Systems

Photochemical Electrocyclic Reactions

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3:31 minutes

Problem 21

Textbook Question

Chorismate mutase is an enzyme that promotes a pericyclic reaction by forcing the substrate to assume the conformation needed for the reaction. The product of the pericyclic reaction is prephenate that is subsequently converted into the amino acids phenylalanine and tyrosine. What kind of a pericyclic reaction does chorismate mutase catalyze?

Verified step by step guidance

Step 1: Analyze the chemical structures of chorismate and prephenate. Chorismate contains a six-membered aromatic ring with substituents including a hydroxyl group, a carboxylate group, and an enol ether. Prephenate, the product, has a six-membered ring with a keto group and a rearranged substituent pattern.

Step 2: Recognize the type of reaction occurring. The transformation involves a rearrangement of bonds within the molecule, characteristic of a pericyclic reaction. Specifically, this reaction is a [3,3]-sigmatropic rearrangement, known as the Claisen rearrangement.

Step 3: Understand the role of chorismate mutase. The enzyme stabilizes the transition state and forces the substrate (chorismate) into a conformation that facilitates the pericyclic reaction. This ensures the reaction proceeds efficiently.

Step 4: Describe the mechanism of the Claisen rearrangement. In this reaction, the enol ether group in chorismate undergoes a concerted rearrangement, where bonds are broken and formed simultaneously, leading to the formation of prephenate.

Step 5: Relate the biological significance. Prephenate is a precursor for the biosynthesis of the amino acids phenylalanine and tyrosine, highlighting the importance of this enzymatic reaction in metabolic pathways.

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Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Pericyclic Reactions

Pericyclic reactions are a class of organic reactions that occur through a concerted mechanism, involving the cyclic rearrangement of electrons. These reactions typically involve the simultaneous breaking and forming of bonds in a cyclic transition state, which can lead to various products. Common types include cycloadditions, electrocyclic reactions, and sigmatropic rearrangements, each characterized by specific electron movement patterns.

Chorismate Mutase Function

Chorismate mutase is an enzyme that catalyzes the conversion of chorismate to prephenate through a pericyclic rearrangement. This enzyme facilitates the necessary conformational change in the substrate, allowing the reaction to proceed efficiently. Understanding its mechanism is crucial for grasping how it influences the biosynthesis of aromatic amino acids like phenylalanine and tyrosine.

Aromatic Amino Acid Biosynthesis

The biosynthesis of aromatic amino acids, such as phenylalanine and tyrosine, is a vital metabolic pathway in organisms. This process begins with chorismate, which is derived from the shikimic acid pathway. The conversion of prephenate into these amino acids involves additional enzymatic steps, highlighting the importance of chorismate mutase in the overall synthesis and regulation of these essential compounds.

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