Interaction between peroxidase and cyclooxygenase activities in prostaglandin-endoperoxide synthase. Interpretation of reaction kinetics.

摘要: Prostaglandin-endoperoxide synthases have two distinct enzymatic activities in the biosynthesis of prostanoids: a peroxidase and fatty acid oxygenase. Hydroperoxides, such as cyclooxygenase reaction product, prostaglandin G2, act both substrates for synthase obligatory initiators itself. A mechanistic scheme was devised to describe interactions between synthase. This mechanism based on heme-dependent that observed with horseradish initiation by intramolecular intermediate. Rate equations derived from were numerically integrated an interactive computer program consolidated diverse phenomena provide quantitative predictions kinetics The agreed well experimental observations purified ovine seminal vesicle enzyme under wide variety conditions, including inhibition exogenous hydroperoxide scavenger cyanide, stimulation hydroperoxide, eicosapentaenoic oxygenation conditions where arachidonic reacts rapidly. detailed analyses made possible simulation important insights into catalytic control biosynthesis.