Which statement about albumin is true?

Which statement about albumin is true?

• A. It is a minor plasma protein with no significant role in drug binding
• B. It binds drugs covalently
• C. It is the enzyme responsible for drug metabolism
• D. It is the most abundant plasma protein and binds many drugs

Answer: (D)

Albumin is the most abundant protein in blood plasma and serves as the main carrier for many drugs by binding them reversibly. This non-covalent, saturable binding means that only the unbound portion of a drug is free to act or be cleared, while the bound portion serves as a reservoir. Because of this binding, changes in albumin levels can alter the free drug concentration and influence both effect and toxicity. Albumin is not an enzyme and does not metabolize drugs—that role belongs to liver enzymes such as the cytochrome P450 system. It’s also not a minor protein, and drugs are not covalently bound to albumin under normal conditions. So the statement that it is the most abundant plasma protein and binds many drugs is the true one.

Albumin is the most abundant protein in blood plasma and serves as the main carrier for many drugs by binding them reversibly. This non-covalent, saturable binding means that only the unbound portion of a drug is free to act or be cleared, while the bound portion serves as a reservoir. Because of this binding, changes in albumin levels can alter the free drug concentration and influence both effect and toxicity. Albumin is not an enzyme and does not metabolize drugs—that role belongs to liver enzymes such as the cytochrome P450 system. It’s also not a minor protein, and drugs are not covalently bound to albumin under normal conditions. So the statement that it is the most abundant plasma protein and binds many drugs is the true one.