Oxidation of nonionic detergents by cytochrome P450 enzymes.
Nonionic phenolic detergents are commonly used in the purification of membrane-associated proteins. Triton N-101 was shown to be oxidized by NADPH-fortified human liver microsomes and recombinant human cytochromes P450 (P450). Oxidation was monitored using HPLC and the fluorescence properties of Triton N-101 and other alkylphenol ethoxylate detergents, which are similar to those of anisole. Human liver microsomes and recombinantly expressed reconstituted P450 3A4-oxidized Triton N-101 in a concentration-dependent manner which could be inhibited by ketoconazole, a P450 3A4-selective inhibitor. Triton N-101 inhibition of testosterone oxidation by human liver microsomes was of a mixed nature but mainly non-competitive. Electrospray ionization mass spectrometry and tandem mass spectrometry indicated that the major product formed was hydroxylated on the alkyl moiety. Human liver microsomes also oxidized other Tritons (X-100 and X-114), Emulgens 911 and 913, and Tergitol NP-10 to a similar extent. P450s 1A1, 1A2, and 2C9 also oxidized Triton N-101 but to a lesser extent than P450 3A4. We conclude that Triton N-101 and similar nonionic detergents are oxidized by P450 3A4 and some other P450s.
Hosea
N A
NA
Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, Tennessee 37232-0146, USA.
Guengerich
F P
FP
D002384:Catalysis; D051544:Cytochrome P-450 CYP3A; D003577:Cytochrome P-450 Enzyme System / Q000378:metabolism*; D003902:Detergents / Q000378:metabolism*; D006801:Humans; D066298:In Vitro Techniques; D008862:Microsomes, Liver / Q000201:enzymology; D006899:Mixed Function Oxygenases / Q000378:metabolism; D017137:Nonoxynol / Q000378:metabolism; D017830:Octoxynol / Q000378:metabolism; D010084:Oxidation-Reduction; D011060:Poloxalene / Q000378:metabolism; D011092:Polyethylene Glycols / Q000378:metabolism; D013050:Spectrometry, Fluorescence; D013054:Spectrophotometry, Atomic; D013739:Testosterone / Q000378:metabolism
D003902:Detergents; C112469:Triton N 101; D017137:Nonoxynol; D011092:Polyethylene Glycols; D013739:Testosterone; D017830:Octoxynol; D011060:Poloxalene; D003577:Cytochrome P-450 Enzyme System; C010615:Nonidet P-40; D006899:Mixed Function Oxygenases; C104464:CYP3A protein, human; D051544:Cytochrome P-450 CYP3A