Membrane phospholipid augments cytochrome P4501a enzymatic activity by modulating structural conformation during detoxification of xenobiotics

• Published in: PloS one 2013-02, Vol.8 (2), p.e57919
• Main Authors: Ghosh, Manik C, Ray, Arun K
• Format: Article
• Language: English
• Subjects: Agrochemicals; Animals; Aromatic hydrocarbons; Biology; Carbofuran; Carbofuran - pharmacology; Catfish; Catfishes; Cytochrome; Cytochrome P-450 CYP1A1 - chemistry; Cytochrome P-450 CYP1A1 - immunology; Cytochrome P-450 CYP1A1 - isolation & purification; Cytochrome P-450 CYP1A1 - metabolism; Cytochrome P450; Cytochrome P4501A; Detoxification; Durapatite - chemistry; Endoplasmic reticulum; Enzymatic activity; Ethanolamines - chemistry; Gene expression; Glycerol; Hepatocytes; Hydrocarbons; Immunoglobulin G - blood; Immunoglobulin G - immunology; Inactivation, Metabolic; Laboratories; Lipids; Lipophilic; Liver; Liver - enzymology; Metabolism; Metabolites; Pesticides; Phosphatidylcholines - pharmacology; Phospholipids; Phospholipids - pharmacology; Physiology; Protein structure; Protein Structure, Secondary - drug effects; Proteins; Structure-function relationships; Toxicity; Xenobiotics; Xenobiotics - pharmacokinetics
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0057919

Cytochrome P450 is a superfamily of membrane-bound hemoprotein that gets involved with the degradation of xenobiotics and internal metabolites. Accumulated body of evidence indicates that phospholipids play a crucial role in determining the enzymatic activity of cytochrome P450 in the microenvironment by modulating its structure during detoxification; however, the structure-function relationship of cytochrome P4501A, a family of enzymes responsible for degrading lipophilic aromatic hydrocarbons, is still not well defined. Inducibility of cytochrome P4501A in cultured catfish hepatocytes in response to carbofuran, a widely used pesticide around the world, was studied earlier in our laboratory. In this present investigation, we observed that treating catfish with carbofuran augmented total phospholipid in the liver. We examined the role of phospholipid on the of cytochrome P4501A-marker enzyme which is known as ethoxyresorufin-O-deethylase (EROD) in the context of structure and function. We purified the carbofuran-induced cytochrome P4501A protein from catfish liver. Subsequently, we examined the enzymatic activity of purified P4501A protein in the presence of phospholipid, and studied how the structure of purified protein was influenced in the phospholipid environment. Membrane phospholipid appeared to accelerate the enzymatic activity of EROD by changing its structural conformation and thus controlling the detoxification of xenobiotics. Our study revealed the missing link of how the cytochrome P450 restores its enzymatic activity by changing its structural conformation in the phospholipid microenvironment.