Aconitase is an iron-sulfur protein containing a [Fe4S4]2+ cluster that catalyzes the stereospecific isomerization of citrate to isocitrate via cis-aconitate. Whereas exposure of aconitase to oxidants renders the enzyme inactive, loss of aconitase activity in cells or in biological samples treated with pro-oxidants has been interpreted as a measure of oxidative damage. Cayman’s Aconitase Assay Kit provides a simple, reproducible, and sensitive tool for assaying aconitase from tissue homogenates or cell lysates. In this assay, citrate is isomerized by aconitase into isocitrate, which is then converted to α-ketoglutarate in a reaction catalyzed by isocitric dehydrogenase. These reactions are monitored by measuring the increase in absorbance at 340 nm associated with the formation of NADPH. The rate of NADPH production is proportional to aconitase activity.
