Question

Which of the following would be the best way to denote that a protein is ready to be recycled so that its amino acids can be reused?

a. Phosphorylate the protein
b. Store the protein as glycogen
c. Add a lipid tail to the protein to anchor it to the membrane
d. Tag the protein with polyubiquitin

Answer 1

Tagging a protein with polyubiquitin signals its readiness for recycling and degradation by the proteasome to reuse its amino acids. Therefore, the correct option is D.

Step-by-step explanation:

The best way to denote that a protein is ready to be recycled so that its amino acids can be reused is by tagging the protein with polyubiquitin. This process involves the addition of ubiquitin groups to the protein, which serves as a signal for degradation. Proteins marked in this way are recognized and transported to the proteasome, an organelle that efficiently degrades proteins, thus releasing the constituent amino acids back into the cell's amino acid pool for reuse.