Brief describtion on the biosynthesis of Ergosterol.

1. BIOSYNTHESIS OF ERGOSTEROL
Microbial Physiology and
Biochemistry
Presented by:
Suby Mon Benny (20LS601032)
Submitted to:
Dr. Sangeetha Menon

2. WHAT IS ERGOSTEROL ?
• It is present in ergot (hence its nomenclature), yeast and the mould
Neurospora.
• Its parent hydrocarbon is ergostane, C28H50.
• Ergosterol has a molecular formula, C28H43OH with one OH group at
C3 and 3 double bonds at C5, C7 and C22.
• It is also optically active.
• Rupture of the ring B by UV radiation produces vitamin D2 which is
chemically known as ergocalciferol. Source: Principles of Biochemistry by
Lehninger

3. IMPORTANCE OF ERGOSTEROL
• It is a component of yeast and other fungal cell membranes,
serving the same functions that cholesterol serves in animal
cells.
• It is a useful target for antifungal drugs.
• Amphotericin B, an antifungal drug, targets ergosterol.
• Ergosterol is a biological precursor of vitamin D2.
• Exposure to ultraviolet light causes a photochemical reaction
that converts ergosterol to ergocalciferol.

4. SYNTHESIS OF ERGOSTEROL

8. Lanosterol
4,4-Dimethyl trienol

11. • The major target of azole antifungal drugs is lanosterol 14-alpha demethylase, a member of
the cytochrome P450 family known as Erg11 protein in many fungal species.
• Squalene epoxidase (Erg1p in S. cerevisiae) is the specific target of allylamine drugs such as
terbinafine.
• Amphotericin B, an antifungal drug, targets ergosterol. It binds physically to ergosterol within
the membrane, thus creating a polar pore in fungal membranes.
• Amphotericin B has been replaced by safer agents in most circumstances.
• Some protozoa, including Trichomonas and Leishmania are inhibited by drugs that target
ergosterol synthesis and function.
ERGOSTEROL AS A TARGET FOR
ANTIFUNGAL AND ANTIPROTOZOAL DRUGS

12. TIME TO BRUSH UP

13. Acetyl Co A
Mevalonate
Acetoacetyl Co A
Geranyl
Diphosphate
Squalene Lanosterol
Zymosterol Episterol Ergosterol
Source: PubChem
Database

14. MY REFERENCES
• Joffrion, Cushion; Sterol biosynthesis and sterol uptake in the fungal
pathogen Pneumocystis carinii; FEMS Microbiology letters; Volume 311,
Issue 1 October 2010, Pg 1-9:
• http://en.Wikipedia.org/wiki/Ergosterol#
• Satyanarayana, Chakrapani; Biochemistry; Books and Allied (P) Ltd; 3rd
edition; Pg 38-39:
• https://pubchem.ncbi.nlm.nih.gov/
• https://pathway.yeastgenome.org/cytoscape-
js/ovsubset.html?orgid=YEAST&pwys=PWY3O-31704