Figure 6

Three-node motifs found in the metabolic networks in different species. The number of connecting nodes for each network is shown. For each motif, the numbers of appearances in real networks (N _real ) and in randomized networks (N _rand ± SD, all values rounded) are shown. The p-values of all motifs are less than 0.01, as determined by comparing to 1000 randomized networks. Each motif occurs at least four times in one network. Motifs were detected and generated using program developed by Milo et al. (2002) and the motif dictionary therein [15].