Scale-rich metabolic networks.

Recent research in biology has clarified many features of the global organization of metabolic networks, including the biochemical mechanisms responsible for power laws in metabolite degrees. The primary aim of this Letter is to give the simplest possible biochemical explanations and minimal toy models based on a highly optimized tolerance perspective, which show where and why metabolic networks have power laws. A second aim is to further explain why scale-free explanations fail in this case to correctly describe metabolism.