Fungal ergosterol biosynthesis enzyme

The term "fungal ergosterol biosynthesis enzyme" refers to any of the suite of enzymes involved in the multi-step pathway that produces **ergosterol**, the principal sterol in fungal cell membranes. Ergosterol is essential for the structural integrity, fluidity, and viability of fungal cells and plays a key role in fungal growth and pathogenesis. The pathway includes over 20 enzymes catalyzing reactions from squalene (mevalonate pathway) to ergosterol via intermediates such as lanosterol and zymosterol. Key enzymes in this process include **lanosterol 14α-demethylase** (Cyp51/Erg11), **squalene epoxidase** (Erg1), **sterol C-8 isomerase** (Erg2), **sterol C-5 desaturase** (Erg3), **sterol C-24 methyltransferase** (Erg6), among others. These enzymes are major targets of clinically important antifungal drugs, with azoles targeting Cyp51, allylamines targeting Erg1, and morpholines inhibiting Erg2. Inhibiting ergosterol synthesis disrupts membrane function and causes fungal death or stasis. Drug resistance often arises from mutations or regulatory changes in these enzyme genes[1][2][4][7]. Despite multiple essential enzymes in the pathway, the term itself is non-specific; structured databases and medical literature usually reference targets by the specific enzyme, such as "Lanosterol 14α-demethylase (Cyp51/Erg11)."[1][4]. Important note: - It is **not** a single canonical molecule or target but refers to a multi-enzyme pathway with many possible specific targets (e.g., Erg11p, Erg1p, Erg2p, etc.)[1][4]. - For precise drug discovery or clinical purposes, the **exact enzyme (like "lanosterol 14α-demethylase") should be specified** rather than the pathway in general. - The current label is **too broad and non-specific** to map directly to existing databases without additional clarification. In summary: "Fungal ergosterol biosynthesis enzyme" is not a unique molecular entity but a general term for any enzyme in the ergosterol biosynthetic pathway in fungi, most notably including lanosterol 14α-demethylase (Cyp51/Erg11), squalene epoxidase (Erg1), and others, which are major antifungal drug targets due to their essential role in fungal membrane synthesis[1][4][7].

Other names

Individual enzymes include Lanosterol 14α-demethylase (also known as Erg11 or Cyp51), Squalene epoxidase (Erg1), Sterol C-8 isomerase (Erg2), C-24 methyltransferase (Erg6), C-5 sterol desaturase (Erg3), C-22 sterol desaturase (Erg5), C-24 sterol reductase (Erg4), and others[1][2][4][5].Collectively sometimes called ergosterol pathway enzyme, erg genes, ergosterol biosynthetic enzymes.

Inhibition of specific ergosterol biosynthetic enzymes, leading to depletion of ergosterol and accumulation of toxic sterol intermediates, which compromises fungal cell membrane integrity and function[1][4][7]. Direct binding to ergosterol in fungal membranes (for polyenes such as amphotericin B), forming pores and causing cell death[6].