Category III solution for five blocked reactions occurring in dermatan sulfate degradation. Iduronic acid (idour, boxed in red) was identified as a root no-consumption metabolite in dermatan sulfate degradation in the lysosome. Flux was restored through the blocked reactions (red arrows) by addition of an extracellular transport function for idour (green arrow). Review of the literature indicates that this SMILEY generated hypothesis is biologically plausible. See text for details.
Rolfsson et al. BMC Systems Biology 2011 5:155 doi:10.1186/1752-0509-5-155