A use of homology modeling and molecular docking methods: to explore binding mechanisms of nonylphenol and bisphenol A with antioxidant enzymes.

Bisphenol A (BPA) and nonylphenol (NP) are phenolic compounds used widely by the industries. BPA and NP are endocrine disruptors possessing estrogenic properties. Several studies have reported that BPA and NP induce oxidative stress in various organs or cell types in animals, by inhibiting the activities of antioxidant enzymes like catalase, superoxide dismutase, glutathione peroxidase, and glutathione reductase. However, it is not understood how BPA and NP interact with these enzymes and inhibit their functions. Hence, it would be significant to check, whether binding sites are available for NP and BPA in antioxidant enzymes. In the present study three-dimensional structures of antioxidant enzymes, catalase, superoxide dismutase, glutathione peroxidase, and glutathione reductase were modeled and docked with BPA and NP. Docking studies revealed that BPA and NP have binding pockets in the antioxidant enzymes. Among the antioxidant enzymes, Catalase was maximally inhibited by BPA and superoxide was maximally inhibited by NP.