The Isocitrate Dehydrogenase Activity Assay kit provides a simple and direct procedure for measuring NADP-+- dependent IDH activity in serum. The activity is determined using isocitrate as the substrate in IDH enzyme reaction. As a result ofthis reaction a change of absorbance at 340 nm is abserved, proportional to the enzymatic activity of IDH One unit of IDHis the amount of enzyme that will generate 1.0 pimole of NADPH per minute at pH 8.0 and 37 °C.