Effect of gallic acid on alkaline phosphatase and peptidase activities in rat intestine.
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Date
2009-10
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Abstract
Gallic acid is a normal constituent of many edible foods, thus directly interacts with epithelial tissue in intestine. In the present study, the effect of gallic acid on intestinal alkaline phosphatase (IAP) and peptidase activities in rat intestine was evaluated. Gallic acid (0.27-0.5 mM) inhibited activities of leucine aminopeptidase (LAP) and -glutamyl transpeptidase (-GTP) by over 90%, compared to controls in rat intestine. In contrast, 0.1-0.6 mM gallic acid either had no effect or stimulated the activity of IAP in rat intestine. The observed inhibition of peptidases by gallic acid was reversible in nature. Kinetic analysis revealed no change in Vmax of LAP (0.42-0.44 units/mg protein) and -GTP (0.22-0.24 units/mg protein), while the values of apparent Km were increased 6-7 fold, exhibiting competitive-type of enzyme inhibition by gallic acid. The values of Ki for LAP and -GTP were 0.037 mM and 0.017 mM, respectively. These observations indicate that gallic acid is a potent inhibitor of brush border peptidases, and thus may interfere in the digestion and absorption of proteins in the intestine.
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Keywords
Leucine aminopeptidase, -Glutamyl transpeptidase, Intestinal alkaline phosphatase, Enzyme inhibition, Gallic acid, Rat intestine, Brush border membrane
Citation
Mahajan Nidhi, Mahmood Akhtar. Effect of gallic acid on alkaline phosphatase and peptidase activities in rat intestine. Indian Journal of Biochemistry & Biophysics. 2009 Oct; 46(5): 378-382.