Table of contents

1. Matter and Measurements4h 31m
2. Atoms and the Periodic Table5h 23m
3. Ionic Compounds2h 18m
4. Molecular Compounds2h 18m
5. Classification & Balancing of Chemical Reactions3h 17m
6. Chemical Reactions & Quantities2h 27m
7. Energy, Rate and Equilibrium3h 46m
8. Gases, Liquids and Solids3h 25m
9. Solutions4h 10m
10. Acids and Bases3h 29m
11. Nuclear Chemistry56m
BONUS: Lab Techniques and Procedures1h 38m
BONUS: Mathematical Operations and Functions47m
12. Introduction to Organic Chemistry1h 34m
13. Alkenes, Alkynes, and Aromatic Compounds2h 12m
14. Compounds with Oxygen or Sulfur1h 6m
15. Aldehydes and Ketones1h 1m
16. Carboxylic Acids and Their Derivatives1h 11m
17. Amines39m
18. Amino Acids and Proteins1h 51m
19. Enzymes1h 37m
20. Carbohydrates1h 41m
21. The Generation of Biochemical Energy2h 8m
22. Carbohydrate Metabolism2h 22m
23. Lipids2h 26m
24. Lipid Metabolism1h 45m
25. Protein and Amino Acid Metabolism1h 37m
26. Nucleic Acids and Protein Synthesis2h 54m

18. Amino Acids and Proteins

Summary of Protein Structure

GOB Chemistry

18. Amino Acids and Proteins

Summary of Protein Structure

Previous problemNext problem

2:55 minutes

Problem 81d

Textbook Question

Consider the amino acids lysine, valine, and aspartate in an enzyme. State which of these amino acids have R groups that would:
d. form salt bridges

Verified step by step guidance

Understand the concept of salt bridges: Salt bridges are ionic interactions that occur between oppositely charged R groups of amino acids in proteins. These interactions typically involve acidic and basic side chains.

Identify the amino acids provided: Lysine, valine, and aspartate. Examine their R groups to determine if they can participate in salt bridge formation.

Analyze lysine: Lysine has a basic R group with an amino group (-NH3+) that can carry a positive charge at physiological pH, making it capable of forming salt bridges with negatively charged groups.

Analyze aspartate: Aspartate has an acidic R group with a carboxylate group (-COO-) that carries a negative charge at physiological pH, allowing it to form salt bridges with positively charged groups.

Analyze valine: Valine has a nonpolar, hydrophobic R group (an isopropyl group) that does not carry a charge and therefore cannot participate in salt bridge formation.

Verified video answer for a similar problem:

This video solution was recommended by our tutors as helpful for the problem above

Video duration:

Play a video:

Was this helpful?

Key Concepts

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

Amino Acid R Groups

Amino acids have unique side chains, known as R groups, that determine their chemical properties and interactions. These R groups can be polar, nonpolar, acidic, or basic, influencing how amino acids behave in proteins. Understanding the nature of these R groups is essential for predicting interactions such as salt bridge formation.

Salt Bridges

Salt bridges are non-covalent interactions that occur between positively and negatively charged R groups of amino acids. They play a crucial role in stabilizing protein structures and are particularly important in enzyme function. In the context of lysine, valine, and aspartate, identifying which amino acids can form these interactions is key to understanding their roles in enzymatic activity.

Acidic and Basic Amino Acids

Amino acids can be classified as acidic or basic based on the nature of their R groups. Aspartate is an acidic amino acid with a negatively charged side chain, while lysine is a basic amino acid with a positively charged side chain. Valine, being nonpolar, does not participate in salt bridge formation, making the distinction between these classifications vital for answering the question.