Catalyzes the formation of pyruvate and succinate from 2-methylisocitrate during the metabolism of endogenous propionyl-CoA. Does not act on isocitrate (By similarity). (2S,3R)-3-hydroxybutane-1,2,3-tricarboxylate = pyruvate + succinate Organic acid metabolism; propanoate degradation. Belongs to the isocitrate lyase/PEP mutase superfamily. Isocitrate lyase family.