What is P-glycoprotein and what does it do?

Question

P-glycoprotein is:

Answer choices

1. A protein that pumps drugs out of cells (efflux).
2. An enzyme involved in drug biotransformation.
3. A transport protein involved in drug absorption.
4. A plasma protein that binds drugs.

Explanation

P-glycoprotein, also called ABCB1/MDR1, is a membrane transporter. It uses ATP to transport its substrates out of the cell.

It is a transport protein, rather than a biotransformation enzyme or a drug-binding plasma protein. Its efflux activity in the intestinal epithelium can limit the entry of its substrates into the body.