[Mechanism of ibuprofen and naproxen interaction with endoperoxide prostaglandin synthetase].

The authors studied the pattern and mechanism of ibuprophen and naproxen interaction with endoperoxideprostaglandin synthetase (PGH synthetase) of sheep vesicular glands. The enzymatic activity of PGH synthetase was determined polarographically with the aid of a Clark electrode. Ibuprophen and naproxen were found to inhibit completely PGH synthetase at concentrations of the order of 1 X 10(-5) M. As regards the mechanism of action both the drugs are competitive inhibitors of this enzyme with reference to arachidonic acid and incompetitive inhibitors with reference to adrenaline, an electron donor.