Determination of arachidonic acid based on the prostaglandin H synthase catalyzed reaction

This article presents a novel method of arachidonic acid (AA) determination based on the reaction catalyzed by prostaglandin H synthase (PGHs). The de oxygenated and nondeoxygenated las control) buffers were used to obtain the PGHs preparations from bovine vesicular glands by two different methods. T he higher specific activity was observed for solubilized preparations obtai ned by ultracentrifugation and deoxygenated buffers. The preparations obtai ned by Ca2+ treatment demonstrated higher stability of PGHs during its stor age at -15 degrees C. To record the initial rate of AA transformation, a sp ectrophotometric assay of PGHs cyclo-oxygenase and peroxidase activities wa s developed using adrenaline and ABTS as electron donors. No oxidation of A BTS was observed in the reaction of AA transformation catalyzed by the PGHs from bovine vesicular glands. However, this electron donor was successfull y used in the reaction catalyzed by PGHs from sheep vesicular glands. No ch emiluminescence was recorded in the reaction of AA transformation catalyzed by PGHs from bovine vesicular glands in the presence of luminol. The chemi luminescent intensity was measured after addition of hydrogen peroxide allo wing quantitative assay of AA to be performed.