Quantitative studies of hydroperoxide reduction by prostaglandin H synthase. Reducing substrate specificity and the relationship of peroxidase to cyclooxygenase activities.

  title={Quantitative studies of hydroperoxide reduction by prostaglandin H synthase. Reducing substrate specificity and the relationship of peroxidase to cyclooxygenase activities.},
  author={Craig Markey and Abdo Alward and Paul E. Weller and Lawrence J. Marnett},
  journal={The Journal of biological chemistry},
  volume={262 13},

Kinetic mechanism of the bifunctional enzyme prostaglandin-H-synthase. Effect of electron donors on the cyclooxygenase reaction

The proposed scheme describes independent but interconnected cyclooxygenase and peroxidase activities of PGHS and explains the experimental data obtained in the present work and known from the literature.

Phenylhydrazones as new good substrates for the dioxygenase and peroxidase reactions of prostaglandin synthase: formation of iron(III)-sigma-phenyl complexes.

A new complex of this hemeprotein characterized by peaks at 438 and 556 nm is formed and is likely the cause of the inhibitory effects previously reported for arylhydrazones toward PGHS.

Similarities in the optical spectra of prostaglandin H synthase during its cyclooxygenase and peroxidase reactions.

  • I. MacdonaldH. Dunford
  • Chemistry, Biology
    Biochemistry and cell biology = Biochimie et biologie cellulaire
  • 1989
The spectral behavior of the enzyme prostaglandin H synthase was studied in the Soret region under conditions that permitted comparison of enzyme intermediates involved in peroxidase and cyclooxygenase activities, and the similarity of the spectra strongly suggests that the enzyme intermediate involved in both the peroxIDase and Cyclo oxygengenase reactions are the same.

The enzymology of prostaglandin endoperoxide H synthases-1 and -2.

  • W. SmithI. Song
  • Biology, Computer Science
    Prostaglandins & other lipid mediators
  • 2002

Inhibition of Prostaglandin H2 Synthases by Salicylate Is Dependent on the Oxidative State of the Enzymes

It is demonstrated that salicylate inhibits PGHS-1 and -2 with a potency inversely related to ambient hydroperoxide concentrations, consistent with an inhibitory action of salicYLate at the PG HS-cyclooxygenase site that is dependent on the PGHS -peroxidase activity.

Peroxidase active site activity assay.

A spectrophotometric assay used to measure the oxidation of a reductant, 2,2'-azino-bis (3-ethylbenzthiazoline-6-sulfonic acid) (ABTS), as well as a high-performance liquid chromatography method for the measurement of the conversion of 5-phenyl-4-pentyl hydroperoxide (PPHP) to its corresponding alcohol.

Analysis of prostaglandin G/H synthase-2 inhibition using peroxidase-induced luminol luminescence.

Inhibition of hCOX-2 activity, measured by luminescence, by a variety of selective and nonselective inhibitors showed rank orders of potency similar to those observed with other in vitro and whole cell methods using the recombinant protein.

Dynamics of Radical Intermediates in Prostaglandin H Synthase-1 Cyclooxygenase Reactions is Modulated by Multiple Factors.

It is demonstrated that equilibrium between arachidonyl radical and tyrosyl radical is shifted by many factors, including temperature, chemical structures of fatty acid substrates and limited supply of oxygen, and is significantly affected by co-substrates of POX.

Prostaglandin synthase-mediated metabolism of carcinogens and a potential role for peroxyl radicals as reactive intermediates.

  • L. Marnett
  • Chemistry, Biology
    Environmental health perspectives
  • 1990
Differences in the relative amounts of hydrolysis products and DNA adducts derived from anti- and syn-dihydrodiolepoxides following application ofBP-7,8-diol to mouse skin in vivo indicate peroxyl radicals play a significant role in metabolism of BP-7-8- diol in uninduced animals.