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 Phosphorylated and inactivated after addition of glucose to the cell culture (repressing conditions). The Vmax with threo-D(S)-isocitrate as substrate is 5-fold higher than with threo-D(S)-2-methylisocitrate as substrate. Optimum pH is 7. Thermostable for 60 minutes up to 50 degrees Celsius. Carbohydrate metabolism; glyoxylate cycle; (S)-malate from isocitrate: step 1/2. Homotetramer. Localizes in extracellular vesicles during growth on lown glucose. When glucose is added to glucose-starved wild-type cells, levels of extracellular ICL1 get reduced. Targeted to the vacuole for degradation in 3-day-starved cells. Repressed by glucose and induced by ethanol via the transcriptional activator CAT8. The promoter sequence located between -397 and -388 contains an upstream activating sequence (UAS)element whereas the sequence located between -261 and -242 contains an upstream repressing sequence (URS) element. Phosphorylated in response to elevated glucose levels, leading first to reversible inactivation of the enzyme (short-term inactivation), and at a later stage to proteolytic degradation of the protein (long-term inactivation). Impairs growth when acetate or ethanol are the sole carbon source. Leads to reduced chronological lifespan. Yeast isocitrate lyase is the only eukaryotic member of this family that is located in the cytoplasm, instead of being targeted to the peroxisome or the glyoxysome. Belongs to the isocitrate lyase/PEP mutase superfamily. Isocitrate lyase family.