Involved in the catabolism of short chain fatty acids (SCFA) via the 2-methylcitrate cycle I (propionate degradation route). Catalyzes the thermodynamically favored C-C bond cleavage of (2R,3S)-2-methylisocitrate to yield pyruvate and succinate via an alpha-carboxy-carbanion intermediate. (2S,3R)-3-hydroxybutane-1,2,3-tricarboxylate = pyruvate + succinate Organic acid metabolism; propanoate degradation. Homotetramer; dimer of dimers. The prpD2B2C2 operon is essential for growth on propionate as sole carbon source. Belongs to the isocitrate lyase/PEP mutase superfamily. Methylisocitrate lyase family. Truncated N-terminus.