Microsomal heme peroxidase activity

Table II. Microsomal Heme Peroxidase Activity in Rats Fed Diets with Altered Vitamin E and/or Selenium Nutrition for 5 Weeks...

These observations suggest that vitamin E may play a regulatory role in PG biosynthesis by controlling the formation of key intermediates such as hydroperoxides and cyclic endoperoxides. In these experiments, peroxidase activity associated with the PGH synthase could not be measured because of the contamination of other peroxidases like cyt P-450 hydroperoxidase in crude microsomal preparations. Our attempts to measure the differences in catalytic rates employing indomethacin were not successful. Nevertheless, it is not too unreasonable to assume that probably both activities of PGH synthase are equally affected by vitamin E deficiency, since both require heme as cofactor. 

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