Which sterol is targeted by amphotericin B?

Which sterol is targeted by amphotericin B?

• A. Cholesterol
• B. Ergosterol
• C. Lanosterol
• D. Desmosterol

Answer: (B)

Amphotericin B works by binding to sterols in fungal membranes, exploiting a difference between fungal and human cells. It has the highest affinity for ergosterol, the main sterol in fungi, and when it binds, the molecule aggregates to form pores that disrupt membrane permeability. This leakage of ions and small molecules collapses the fungal cell’s homeostasis and leads to death. The selectivity comes from the structural differences between ergosterol and cholesterol; while the drug can bind cholesterol too, its strongest effect is with ergosterol, which is why it’s antifungal. Lanosterol and desmosterol are precursors in sterol biosynthesis and are not the primary targets for pore formation by this drug.

Amphotericin B works by binding to sterols in fungal membranes, exploiting a difference between fungal and human cells. It has the highest affinity for ergosterol, the main sterol in fungi, and when it binds, the molecule aggregates to form pores that disrupt membrane permeability. This leakage of ions and small molecules collapses the fungal cell’s homeostasis and leads to death. The selectivity comes from the structural differences between ergosterol and cholesterol; while the drug can bind cholesterol too, its strongest effect is with ergosterol, which is why it’s antifungal. Lanosterol and desmosterol are precursors in sterol biosynthesis and are not the primary targets for pore formation by this drug.