Question

A protein is regulated by a protein kinase and a protein phosphatase, and is active when phosphorylated. What would decrease the protein's activity?

1) Increase in protein kinase activity
2) Decrease in protein phosphatase activity
3) Increase in protein phosphatase activity
4) Decrease in protein kinase activity

Answer 1

Increasing protein phosphatase activity would decrease the protein's activity.

Step-by-step explanation:

A protein can be regulated by a protein kinase and a protein phosphatase, and its activity is determined by phosphorylation. To decrease the protein's activity, we need to reduce phosphorylation. Phosphorylation is carried out by protein kinases and can be reversed by protein phosphatases.

Therefore, option 3) Increase in protein phosphatase activity would decrease the protein's activity. Protein phosphatases remove the phosphate group from phosphorylated amino acid residues, thus reversing phosphorylation and inactivating the protein.