Topology of the signaling and metabolic pathway of eicosanoid production in human. The known pathway topology was simplified by Gupta et al.  based on the availability of metabolite concentration data in their experiments. The rectangles show the metabolites and the solid arrows indicate the metabolic transformations involved. The ellipses with dashed borders show the enzymes catalyzing the metabolic transformations between two metabolites that are neighboring it in the graph. The dashed lines denote the effect of enzymes and molecules on the activity of enzymes.