Isocitrate lyase is an enzyme of the glyoxylate cycle that catalyzes the reaction below:

Isocitrate <=> Succinate + Glyoxylate

This enzyme, which is present in plants and bacteria, allows for net syntheis of glucose using a two-carbon source, such as acetyl-CoA from breakdown of fatty acids. Because animals do not have isocitrate lyase, they cannot synthesize glucose in net amounts from fat.