Localization of Gastric Peroxidase and Its Inhibition by Mercaptomethylimidazole, an Inducer of Gastric Acid Secretion
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Mercaptomethylimidazole (MMI) is a potent inducer of gastric acid secretion which is associated with significant inhibition of peroxidase activity of rat gastric mucosa in vivo. A time-dependent increase in acid secretion correlates well with time-dependent decrease in the peroxidase activity. In a chamber experiment in vitro using isolated gastric mucosa, MMI stimulates acid secretion, showing an almost linear response up to 600 microM. The time-dependent increase in acid secretion is also correlated with time-dependent inhibition of the peroxidase activity. This effect is not mediated through oxidation of MMI by flavin-containing mono-oxygenase, which is absent from gastric mucosa. The peroxidase has been localized mainly in parietal cells isolated and purified from gastric mucosa by controlled digestion with collagenase followed by Percoll-density-gradient centrifugation. Peroxidase activity was further localized in the outer membrane of the purified mitochondria of the parietal cell by some membrane-impermeant reagents, indicating outward orientation of the enzyme. MMI can inhibit the peroxidase activity of both the parietal cell and its mitochondria in a concentration-dependent manner. The possible involvement of the parietal-cell peroxidase-H2O2 system in MMI-induced acid secretion may be suggested.
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Whittemore J, Mooney A, Price J, Thomason J J Vet Intern Med. 2019; 33(6):2618-2627.
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Whittemore J, Mooney A, Price J, Thomason J J Vet Intern Med. 2019; 33(5):1977-1987.
PMID: 31397009 PMC: 6766539. DOI: 10.1111/jvim.15577.
Bandyopadhyay U, Biswas K, Bandyopadhyay D, Ganguly C, Banerjee R Mol Cell Biochem. 2000; 202(1-2):31-6.
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Das D, Banerjee R Mol Cell Biochem. 1993; 125(2):115-25.
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