20.4. METABOLIC NETWORKS 631
databases [ABH94, KGKN02, OLP
+
00]. Visualizations of metabolic pathways should help
understanding the interconnections between metabolites, analyzin g the flow of substances
through the network and identifying main and alternative paths. The established presen-
tation styles and discussions with users result in several visualization requirements [Sch02]:
1. Parts of reactions: The display of substances and enzymes is application and
user-specific. Usually for main sub s tanc es their name, s tr u ct ur al formula or both
should be shown. Co-substances should be dis p layed using their name or abbre-
viation and enzymes should be represented by their name or EC-number [Int92].
2. Reactions: The reaction arrow(s) should b