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P Wlodawer

Publications and source records attributed to P Wlodawer.

15 recordsLinked to original sources
PubMed1980

Conversions of prostaglandin endoperoxides by prostacyclin synthase from pig aorta.

Partially purified prostacyclin synthase from pig aorta converted the prostaglandin (PG) endoperoxide PGH2 to prostacyclin (PGI2), and PGH1 to 12-hydroxy-8,10-heptadecadienoic acid (HHD). Both reactions were inhibited by 15-hydroperoxy-5,8,11,13-eicosatetraenoic acid (15-HP) in a dose-dependent rashion. However, the reactions PGH2 leads to PGI2 and PGH1 leads to HHD appeared to differ: substrate availability was rate limiting in the latter reaction, while the enzyme became rapidly saturated witth PGH2 and a steady rate of prostacyclin formation was observed at higher substrate levels.

6-Ketoprostaglandin F1 alpha↗
PubMed1976

Biosynthesis of prostaglandin F2alpha from arachidonic acid and prostaglandin endoperoxides in the uterus.

Formation of prostaglandin F2Alpha in the cow and guinea pig uterus microsomes was studied using 14C-labeled arachidonic acid and prostaglandin H2. The total conversion of arachidonic acid was of a low order and underwent fluctuations during the estrous cycle of the guinea pig, being highest towards the end of the cycle. Injections of beta-estradiol-3-benzoate also resulted in higher activity of the uterine prostaglandin synthetase. The uterine prostaglandin synthesizing system appeared to differ in several respects from that present in seminal vesicles, with regard to the proportions of the products formed and the effects of various agents, e.g. reduced glutathione. An inhibiting factor which supressed the fatty acid cyclo-oxygenase was found to be present in uterine preparations. Prostaglandin endoperoxide (prostaglandin H2) was very efficiently reduced to prostaglandin F2alpha by cow and guinea-pig uterus microsomes. Prostaglandin G2 also gave rise to prostaglandin F2alpha. Prostaglandin E2, on the other hand, was not reduced. Both the inhibiting factor and the endoperoxide reducing activity are likely to be parts of a highly specialized mechanism that modulates prostaglandin F2alpha formation in the uterus.

Animals↗
PubMed1975

Co-oxygenation of organic substrates by the prostaglandin synthetase of sheep vesicular gland.

The microsomal fraction of sheep vesicular glands has been found to oxygenate 1,3-diphenylisobenzofuran, luminol, and the carcinogenic hydrocarbon benzopyrene when incubated with arachidonic acid. The oxygenations demonstrate an absolute dependence on enzyme and fatty acid and can be completely inhibited by indomethacin and 2,3-dimercaproptopanol, inhibitors of prostaglandin synthetase. The oxygenations can also be stimulated by the hydroperoxy endoperoxide, prostaglandin G2, and 15-hydroperoxy-5,8,11,13-eicosatetraenoic acid. These latter reactions are not inhibited by indomethacin or dimercaptopropanol but do require the microsomal enzyme system. The involvement of superoxide anion in the transformations could not be demonstrated. The oxygenations occurring in the presence of arachidonic acid appear to arise via the interaction of a microsomal enzyme system with hydroperoxide intermediates of prostaglandin biosynthesis. The ability of various sulfur reagents (reduced glutathione, alpha-lipoic acid, methional) to inhibit co-oxygenation is probably related to their ability to stimulate the conversion of the intermediate to prostaglandins.

Animals↗