The demo network is the union of all paths annotated for S. cerevisiae in BioCyc release 10.6. It is an undirected graph consisting of 2,656 edges. The seed nodes are the start and end compound of the heme biosynthesis II pathway as annotated in BioCyc. This pathway is one of the study cases described in Croes et al., J. Mol. Biol. 356: 222-236 (see our list of publications.) Note that for this demo, path finding is done on a smaller, undirected graph without differentially weighting compounds and reactions (both receive a weight according to their degree). To find paths in directed metabolic networks with mutually exclusive reaction directions, check the advanced options of the Pathfinder tool. Use the Metabolic path finding tool to find paths in the complete KEGG network. The path of first rank corresponds to the annotated heme biosynthesis II pathway. To see the influence of the weighting scheme, you can set the weighting scheme to unit weight and the rank to 1 (for quicker computation). You will obtain an entirely different result.