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

29. Amino Acids

Proteins and Amino Acids

Organic Chemistry

29. Amino Acids

Proteins and Amino Acids

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7:42 minutes

Problem 42

Textbook Question

Proof that an imine was formed between aldolase and its substrate was obtained by using D-fructose-1,6-bisphosphate labeled at the C-2 position with ¹⁴C as the substrate. NaBH₄ was added to the reaction mixture. A radioactive product was isolated from the reaction mixture and hydrolyzed in an acidic solution. Draw the structure of the radioactive product obtained from the acidic solution. (Hint: NaBH₄ reduces an imine linkage.)

Verified step by step guidance

Understand the reaction mechanism: The problem involves the formation of an imine intermediate between aldolase and its substrate, D-fructose-1,6-bisphosphate, labeled with 14C at the C-2 position. Imine formation occurs when a primary amine reacts with a carbonyl group, resulting in a C=N bond.

Recognize the role of NaBH4: Sodium borohydride (NaBH4) is a reducing agent that specifically reduces imines (C=N) to amines (C-N). This reduction step is crucial for stabilizing the intermediate and isolating the product.

Predict the radioactive product after NaBH4 reduction: After NaBH4 reduces the imine, the resulting product will have a C-N bond at the position where the imine was formed. The 14C label at the C-2 position will remain intact, as the reduction does not affect the carbon labeling.

Understand the hydrolysis step: The hydrolysis in acidic solution will cleave the bond between the enzyme and the substrate, releasing the reduced substrate as the final product. The structure of the product will include the reduced amine group and the intact D-fructose-1,6-bisphosphate backbone with the 14C label at C-2.

Draw the structure of the final product: The final product will be D-fructose-1,6-bisphosphate with a reduced amine group at the position where the imine was formed. Ensure the 14C label is clearly indicated at the C-2 position in the structure.

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Key Concepts

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

Imine Formation

Imine formation occurs when a carbonyl compound, such as an aldehyde or ketone, reacts with an amine, resulting in the creation of a C=N bond. This reaction is typically facilitated by the removal of water, which drives the equilibrium towards imine formation. Understanding this process is crucial for analyzing the reaction between aldolase and its substrate, as the formation of an imine is a key step in the mechanism.

Reduction with NaBH4

Sodium borohydride (NaBH4) is a selective reducing agent commonly used in organic chemistry to reduce carbonyl compounds, including imines, to their corresponding amines. In the context of the question, NaBH4 reduces the imine linkage formed between aldolase and the substrate, leading to the formation of a stable amine product. This reduction is essential for understanding the transformation of the imine into a detectable product.

Radioactive Labeling

Radioactive labeling involves incorporating a radioactive isotope, such as 14C, into a molecule to trace its path through a chemical reaction. In this case, d-fructose-1,6-bisphosphate is labeled at the C-2 position, allowing researchers to track the formation of the radioactive product. This technique is vital for confirming the structure of the product and understanding the reaction mechanism, as it provides a means to identify and isolate specific compounds.

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