Involved in the metabolic adaptation in response to environmental changes. Catalyzes the reversible 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 during growth on fatty acid substrates. May be involved in the assimilation of one-carbon compounds via the isocitrate lyase-positive serine pathway. D-threo-isocitrate = glyoxylate + succinate Can also use Mn(2+). In the presence of magnesium, inhibited by oxalate, potassium cyanide, manganese, silver, cadmium and to a lesser extent by succinate, glycolate, iodoacetamide, DL-penicillamine, aluminum, sodium, potassium, lithium and strontium. Optimum pH is 7.5. The enzyme is stable when incubated for 15 min at 30 degrees Celsius at pH 7.5-9. Optimum temperature is 45 degrees Celsius. Loss of activity is 0%, 16%, 30%, 82% and 100% when incubated at 25, 30, 40, 50 and 60 degrees Celsius for 30 min, respectively. Carbohydrate metabolism; glyoxylate cycle; (S)-malate from isocitrate: step 1/2. One-carbon metabolism; formaldehyde assimilation via serine pathway. Homotetramer. Belongs to the isocitrate lyase/PEP mutase superfamily. Isocitrate lyase family.