Table of contents

1. Introduction to Biochemistry4h 34m
2. Water3h 23m
3. Amino Acids8h 10m
4. Protein Structure10h 4m
5. Protein Techniques14h 5m
6. Enzymes and Enzyme Kinetics13h 38m
7. Enzyme Inhibition and Regulation 8h 42m
8. Protein Function 9h 41m
9. Carbohydrates7h 49m
10. Lipids5h 49m
11. Biological Membranes and Transport 6h 37m
12. Biosignaling9h 45m
Review 1: Nucleic Acids, Lipids, & Membranes2h 47m
Review 2: Biosignaling, Glycolysis, Gluconeogenesis, & PP-Pathway3h 12m
Review 3: Pyruvate & Fatty Acid Oxidation, Citric Acid Cycle, & Glycogen Metabolism2h 26m
Review 4: Amino Acid Oxidation, Oxidative Phosphorylation, & Photophosphorylation1h 48m

8. Protein Function

Heme Prosthetic Group

Biochemistry

8. Protein Function

Heme Prosthetic Group

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Multiple Choice

The distal histidine residue in myoglobin acts to:

Prevent oxidation of the heme Fe²⁺.

Lower the relative affinity for CO.

Assist in the binding of O₂.

Prevent release of N₂.

a & b.

a, b & c.

All the above are true.

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Verified step by step guidance

Understand the role of the distal histidine in myoglobin: The distal histidine is a key amino acid residue located near the heme group in myoglobin. It plays a crucial role in stabilizing the binding of oxygen (O2) to the heme iron (Fe2+).

Examine how the distal histidine prevents oxidation of the heme Fe2+: The distal histidine helps to prevent the oxidation of the heme iron from Fe2+ to Fe3+, which is essential for maintaining the ability of myoglobin to bind oxygen effectively.

Analyze how the distal histidine lowers the relative affinity for carbon monoxide (CO): The distal histidine creates steric hindrance and forms hydrogen bonds that reduce the binding affinity of CO to the heme iron, thus favoring the binding of O2 over CO.

Explore how the distal histidine assists in the binding of O2: The distal histidine stabilizes the bound O2 molecule through hydrogen bonding, which enhances the affinity of myoglobin for oxygen.

Conclude that the distal histidine does not prevent the release of N2: Nitrogen (N2) is not typically bound by myoglobin, so the distal histidine does not play a role in preventing its release. Therefore, the correct answer includes a, b, and c, as these are the functions of the distal histidine in myoglobin.