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Mechanism of azole antifungal activity as determined by liquid chromatographic/mass spectrometric monitoring of ergosterol biosynthesis
Author(s) -
Heimark Larry,
Shipkova Petia,
Greene Jonathan,
Munayyer Hanan,
YaroshTomaine Taisa,
DiDomenico Beth,
Hare Roberta,
Pramanik Birendra N.
Publication year - 2002
Publication title -
journal of mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.475
H-Index - 121
eISSN - 1096-9888
pISSN - 1076-5174
DOI - 10.1002/jms.280
Subject(s) - ergosterol , chemistry , lanosterol , sterol , posaconazole , biosynthesis , chromatography , mass spectrometry , mass spectrum , azole , biochemistry , stereochemistry , antifungal , enzyme , itraconazole , cholesterol , microbiology and biotechnology , biology
A liquid chromatography/mass spectrometry (LC/MS) method for separation and characterization of ergosterol biosynthetic precursors was developed to study the effect of Posaconazole on sterol biosynthesis in fungi. Ergosterol biosynthetic precursors were characterized from their electron ionization mass spectra acquired by a normal‐phase chromatography, particle beam LC/MS method. Fragment ions resulting from cleavage across the D‐ring and an abundant M − 15 fragment ion were diagnostic for methyl substitution at C‐4 and C‐14. Comparison of the sterol profile in control and treated Candida albicans incubations showed depletion of ergosterol and accumulation of C‐4 and C‐14 methyl‐substituted sterols following treatment with Posaconazole. These C‐4 and C‐14 methyl sterols are known to be incapable of sustaining cell growth. The results demonstrate that Posaconazole exerts its antifungal activity by inhibition of ergosterol biosynthesis. Furthermore, Posaconazole appears to disrupt ergosterol biosynthesis by inhibition of lanosterol 14α‐demethylase. Copyright © 2002 John Wiley & Sons, Ltd.