Creative Enzymes’ expertise lies in customization of activity measurement for oxidoreductases. Based on the excellent techniques and professional process, Creative Enzymes has obtained a good reputation in the enzymatic activity industry. We offer accurate and rapid testing services for a variety of enzymes, including isocitrate dehydrogenase (NAD⁺).

Isocitrate dehydrogenase (ICDH) is an enzyme that participates in the tricarboxylic acid (TCA) cycle. It catalyzes the dehydrogenation and subsequent decarboxylation of isocitrate and produces α-ketoglutarate and CO₂ using NAD or NADP as a cofactor. Isocitrate dehydrogenase (NAD⁺) is an NAD⁺-linked enzyme found only in mitochondria and displaying allosteric properties. The enzyme from some species can also use NADP⁺ but the catalysis efficiency is much lower. This enzyme requires Mn²⁺ or Mg²⁺ for its activity. Notably, unlike EC 1.1.1.42 (isocitrate dehydrogenase (NADP⁺)), oxalosuccinate cannot be used as a substrate for isocitrate dehydrogenase (NAD⁺). The enzyme is widely distributed among archaea, bacteria, and eukarya. The alternative names of EC 1.1.1.41 are:

• isocitric dehydrogenase;
• beta-ketoglutaric-isocitric carboxylase;
• isocitric acid dehydrogenase;
• NAD dependent isocitrate dehydrogenase;
• NAD isocitrate dehydrogenase;
• NAD-linked isocitrate dehydrogenase;
• NAD-specific isocitrate dehydrogenase;
• NAD isocitric dehydrogenase;
• isocitrate dehydrogenase (NAD);
• IDH (ambiguous);
• nicotinamide adenine dinucleotide isocitrate dehydrogenase

The oxidative decarboxylation of isocitrate to α-ketoglutarate catalyzed by mitochondrial isocitrate dehydrogenase (NAD⁺) is a rate-limiting step in the tricarboxylic acid (TCA) cycle. Many design efforts have been done to change the specificity utilization of NAD⁺ or to improve the activity of this enzyme. For example, multiple mutations at the cofactor-binding site successfully switched the specificity of preference for NAD⁺ over NADP⁺. Due to the vital position in TCA cycle, isocitrate dehydrogenase (NAD⁺) has become an interested target for many researchers. Proper activity assay method could support research in a rapid and accurate manner. Creative Enzymes uses advanced spectrophotometric equipment to provide reliable analysis for isocitrate dehydrogenase (NAD⁺).

Figure: The crystal structure of NAD dependent isocitrate dehydrogenase from Acidithiobacillus thiooxidans.
Reference: Imada K et al. Proteins. 2008 70(1):63-71.

Creative Enzymes is an expert in enzyme activity measurement. With the skilled specialists and advanced instruments, Creative Enzymes sets up the new standard in the enzyme assay industury. In the furture, we will continue the support to your research with high-qulity services.