Hepatic microsomal ethanol oxidizing system (MEOS): Differentiation from alcohol dehydrogenase and NADPH oxidase

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Abstract

Washed hepatic microsomes contain an active ethanol oxidizing system (MEOS) but no detectable ADH activity, even when 3-AP-NAD is used as a cofactor. ADH inhibitors (pyrazole and DMSO) failed to affect MEOS activity at concentrations which markedly reduced ADH activity. Therefore ADH is not a component of MEOS. Cholate, which inhibits the activities of both microsomal NADPH oxidase and MEOS, also strikingly diminishes that of other microsomal enzymes such as aniline hydroxylase and aminopyrine demethylase. Furthermore cholate inactivates both total and enzymatically reducible microsomal cytochrome P450. Thus, because of the non-specific nature of the inhibition by cholate, one cannot conclude from its effects that NADPH oxidase is a component of MEOS.

References (23)

  • C.S. Lieber et al.

    J. Biol. Chem

    (1970)
  • M.K. Roach et al.

    Bioche. Biophys. Res. Commun

    (1969)
  • R.K. Bonnichsen et al.
  • N.O. Kaplan et al.

    J. Biol. Chem

    (1956)
  • Y. Imai et al.

    Biochem. Biophys. Res. Commun

    (1966)
  • T. Omura et al.

    J. Biol. Chem

    (1964)
  • F. Hutterer et al.

    Life Sci

    (1970)
  • C.S. Lieber et al.

    Science

    (1968)
  • K.J. Isselbacher et al.

    Biochem. Biophys. Res. Commun

    (1970)
  • J.R. Gillette et al.

    J. Pharmacol. Exp. Ther

    (1957)
  • D. Keilin et al.

    Biochem. J

    (1945)
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      Ongoing cycles of high levels of ethanol abuse and ethanol metabolism represent a primary mechanism of organ damage and is one major contributing factor resulting in the pathology of ALD and subsequent development of late-stage ALD (Han et al., 2012). Ethanol is primarily metabolized in the liver by cytosolic alcohol dehydrogenase (ADH) and the inducible cytochrome P450 2E1 (CYP2E1) in mitochondria and endoplasmic reticulum (Lieber, Rubin, & DeCarli, 1970; Seitz et al., 2018). The metabolism of ethanol by ADH1 and CYP2E1 results in the oxidation of ethanol to acetaldehyde (ACH), a highly reactive and toxic metabolite, which is then further metabolized to acetate by aldehyde dehydrogenase (ALDH2) located in the mitochondria in the liver.

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    These studies were supported by USPHS grants MH 1558 and AM 12511.

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