Aconitase Enzyme Activity Microplate Assay Kit is a simple, reproducible, and sensitive tool for assaying aconitase from tissue homogenates or cell lysates. Unlike other assays this is not a coupled reaction and therefore only aconitase activity is required and measured. Aconitase catalyzes an equilibrium between aconitate, cis-aconitate and iso-citrate. These reactions are monitored by measuring the increase in absorbance at 240 nm associated with the formation of the cis-aconitate which has an extinction coefficient of 2.2 OD/mM per well. Therefore the rate of cis-aconitate production is proportional to aconitase activity.Aconitase (aconitate hydratase; EC 4.2.1.3) is an iron-sulfur protein that catalyzes the reversible inter-conversion of citrate and isocitrate, via a cis-aconitate intermediate, in both the TCA and glyoxylate cycles. The enzyme contains a [4Fe-4S] cluster which interacts directly with the substrates. In eukaryotes there are both mitochondrial and cytosolic forms of the enzyme.