[Deperoxidation of hydroperoxylinoleic acid by the intestinal mucosa]

In the presence of glutathione, a homogenate of rat intestinal mucosa transforms linoleic acid hydroperoxide (LOOH) into the corresponding alcohol (LOH). The Km of the enzyme involved (a glutathione peroxidase) is 5.7 x 10(-6) M. The specific activity, measured as generated LOH, was found to be 0.058 mumol/mg protein/min, six times lower than that of the liver. A mitochondrial supernatant of the mucosal homogenate had 1.5 times the activity of the initial homogenate. The reduction of 1 mol LOOH requires 2 mol glutathione. Besides this enzymatic deperoxidation, 5% of the LOOH was decomposed in both the intestinal mucosa and liver by a non-enzymatic pathway, probably involving the Fe3+ of the haemoproteins.