DL-threo-2-methylisocitrate is a substrate of isocitrate lyase 1 (ICL1). Using Michaelis-Menten nonlinear least squares fitting, the kcat value was determined to be 5.24 s-1, and the Km of the purified recombinant ICL1 for threonine-D(s)L(s)-isocitrate (ICA) was 188 μM.