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Cell-free Biochemical Fluorometric Enzymatic Assay for High-throughput Measurement of Lipid Peroxidation in High Density Lipoprotein
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Cell-free Biochemical Fluorometric Enzymatic Assay for High-throughput Measurement of Lipid Peroxidation in High Density Lipoprotein

Published on: October 12, 2017

Effect of dietary vitamin E on methyl ethyl ketone peroxide damage to microsomal cytochrome P-450 peroxidase

M Ando, A L Tappel

    Chemico-Biological Interactions
    |November 1, 1985
    PubMed

    Insights

    Dietary vitamin E protects against methyl ethyl ketone peroxide (MEKP) damage to liver enzymes. Supplementation with vitamin E and reductants like NADH/NADPH is crucial for endoplasmic reticulum protection from toxic peroxides.

    Area of Science:

    • Biochemistry
    • Toxicology
    • Nutritional Science

    Background:

    • Methyl ethyl ketone peroxide (MEKP) is a toxic organic peroxide.
    • Cytochrome P-450 enzymes are vital for metabolizing xenobiotics and endogenous compounds.
    • Oxidative stress can damage cellular components, including microsomal enzymes.

    Purpose of the Study:

    • To investigate the protective effects of dietary vitamin E against MEKP-induced damage to cytochrome P-450 and associated enzymes.
    • To elucidate the role of vitamin E and reductants (NADH, NADPH) in mitigating MEKP toxicity in vivo and in vitro.

    Main Methods:

    • In vivo studies using vitamin E-deficient and supplemented rats.
    • In vitro assays measuring enzyme activity (aminopyrine demethylase, TMPD-peroxidase, NADH-peroxidase) and thiobarbituric acid reacting substances (TBARS) production.
    • Administration of MEKP to rat liver microsomes.

    Main Results:

    • MEKP caused significant damage to microsomal cytochrome P-450 and peroxidases in vitamin E-deficient rats.
    • Dietary vitamin E supplementation protected these enzymes from MEKP-induced damage.
    • In vitro, MEKP inhibited enzyme activities differently, and induced more TBARS in microsomes from deficient rats.
    • NADH and NADPH significantly reduced MEKP's inhibitory effects and TBARS generation.

    Conclusions:

    • Dietary vitamin E plays a critical role in protecting against MEKP-induced oxidative damage to liver microsomal enzymes.
    • Adequate levels of vitamin E, NADH, and NADPH are essential for protecting the endoplasmic reticulum from toxic organic peroxides like MEKP.

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