This enzyme belongs to the family of lyases, specifically the oxo-acid-lyases, which cleave carbon-carbon bonds.

During catalysis, isocitrate is deprotonated, and an aldol cleavage results in the release of succinate and glyoxylate.

This reaction mechanism functions much like that of aldolase in glycolysis, where a carbon-carbon bond is cleaved and an aldehyde is released.

In eukaryotes, the additional amino acids are thought to function in the localization of ICL to single-membrane-bound organelles called glyoxysomes.

[11] In vitro studies showed that both Rv1915 (ICL2a) and Rv1916 (ICL2b) may be able to catalyze the conversion of isocitrate to form succinate and glyoxylate.

The most frequently-used assays involved the use of chemical or enzyme-coupled ultraviolet–visible (UV/vis) spectroscopy to measure the amount of glyoxylate that is being formed.

[15][16] The ICL enzyme has been found to be functional in various archaea, bacteria, protists, plants, fungi, and nematodes.

As a result, organisms that use ICL and malate synthase are able to synthesize glucose and its metabolic intermediates from acetyl-CoA derived from acetate or from the degradation of ethanol, fatty acids, or poly-β-hydroxybutyrate.

[9][19] This is important because the methylcitrate cycle is key for the survival of the bacteria on odd-chain fatty acids.

[4] For several agricultural crops including cereals, cucumbers, and melons, increased expression of the gene encoding ICL is important for fungal virulence.

This is the case for fungi such as Candida albicans, which inhabits the skin, mouth, GI tract, gut and vagina of mammals and can lead to systemic infections of immunocompromised patients; as well as for the bacterium Mycobacterium tuberculosis, the major causative agent of tuberculosis.

[4][26][27] More research is needed to identify inhibitors that selectively target enzymes in the glyoxylate cycle.