Catalyzes the formation of succinate and glyoxylate from isocitrate, a key step of the glyoxylate cycle, which operates as an anaplerotic route for replenishing the tricarboxylic acid cycle. Required for growth on ethanol or acetate, but dispensable when fermentable carbon sources are available. Acts also on 2-methylisocitrate. D-threo-isocitrate = glyoxylate + succinate (2S,3R)-3-hydroxybutane-1,2,3-tricarboxylate = pyruvate + succinate Carbohydrate metabolism; glyoxylate cycle; (S)-malate from isocitrate: step 1/2. Homotetramer. Inhibits the utilization of acetate, ethanol, and fatty acids, but also reduces the growth rate on glucose. Belongs to the isocitrate lyase/PEP mutase superfamily. Isocitrate lyase family.