The phase-plane portraits for FA-FAS, FA-ACCase and FA-MalCoA. Low malonyl-CoA dissociation constant (K1 = 0.5, orange line), which corresponds to strong malonyl-CoA inhibition, leads to multiplicity of steady states pattern between FAS-FA and MalCoA-FA input-output relationships. (For interpretation of the references to color in this figure legend, the reader is referred to the Web version of this article.)