Phosphatidate phosphatase of dermatophytes

Area of Science:

• Biochemistry
• Mycology
• Enzymology

Background:

• Pathogenic fungi, including dermatophytes, possess enzymes crucial for their survival and virulence.
• Phosphatidate phosphatase (EC 3.1.3.4) plays a key role in lipid metabolism.

Purpose of the Study:

• To characterize phosphatidate phosphatase in filamentous pathogenic fungi, specifically Microsporum gypseum and Epidermophyton floccosum.
• To investigate the subcellular localization, optimal pH, and sensitivity to inhibitors of this enzyme.

Main Methods:

• Enzyme assays were performed on mitochondrial and microsomal fractions of M. gypseum and E. floccosum.
• The effects of various metal ions (Fe2+, Mn2+, Cu2+, Ba2+, Hg2+, Mg2+), sulfhydryl reagents, and phospholipids (phosphorylcholine, lysophosphatidylcholine, phosphatidylcholine) on enzyme activity were assessed.

Main Results:

• Phosphatidate phosphatase was detected in both mitochondrial and microsomal fractions of both fungal species, with a pH optimum of 6.0.
• The enzyme from E. floccosum was more active than that from M. gypseum.
• Both enzymes were inhibited by several divalent metal ions, with the E. floccosum microsomal enzyme showing complete inhibition by Mn2+ and Fe2+. Mg2+ dependency was observed in the presence of EDTA.
• Sulfhydryl reagents did not inhibit the enzyme. Phosphorylcholine and lysophosphatidylcholine caused significant inhibition, while phosphatidylcholine showed less inhibition.

Conclusions:

• Phosphatidate phosphatase is present in pathogenic dermatophytes and exhibits distinct properties in different subcellular fractions and species.
• The enzyme's sensitivity to specific metal ions and phospholipids suggests potential regulatory mechanisms and targets for antifungal strategies.