Biosynthesis of ergosterol

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, C 28 H 50 . Ergosterol has a molecular formula, C 28 H 43 OH 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

5. Lanosterol 4,4-Dimethyl trienol

6. 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 Amphotericin B has been replaced by safer agents in most circumstances.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

7. Time to brush up

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

9. 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; 3 rd edition; Pg 38-39: https://pubchem.ncbi.nlm.nih.gov/ https://pathway.yeastgenome.org/cytoscape-js/ovsubset.html?orgid=YEAST&pwys=PWY3O-31704