Figure 3

Drug synergisms for the human metabolic network. Left panel:For each affected pathway, the histogram reports the number of objectivereactions which can be stopped; gray-scale bars represent reactions stoppedonly by a Single drug or multidrug solution, classified as Newinhibition (meaning that no single drug is capable of triggering theinhibition), More selective and Less selective inhibitions(referring to the case where both single and multiple drug treatments arepossible and the multiple one has respectively a lower and a higher sideeffect). Right panels: The two plots refer to multiple drug solutionsonly. For the same pathways as in the left panel, we report here the fractionof the direct drug targets and the fraction of the synergistic inhibitionswhich are induced by the six classes of synergisms (shown in Figure 2): the comparison between the two stacks shows thatsynergistic interactions can occur on pathways that are not direct targets ofthe drugs.