ergosterol

1. (biochemistry, steroids, mycology) The steroid precursor of vitamin D₂. It is found in cell membranes of fungi, and is their functional equivalent of cholesterol. It is also found in the membranes of some protists.Examples: "Terbinafine has a unique mechanism of action among the antifugal agents (Petranyi et al, 1984; Balfour and Faulds, 1992), inhibiting the synthesis of ergosterol, a key sterol component in the plasma membrane of the fungal cell."countableuncountable