IDH3A also known as RP90 is a member of  the isocitrate and isopropylmalate dehydrogenases family.. IDH3A plays a vital role in cellular metabolism by catalyzing the oxidative decarboxylation of isocitrate to produce 2-oxoglutarate, a key intermediate essential for various biosynthetic pathways and energy production. IDH3A contributes to the regulation of the TCA cycle and influences the balance of metabolic intermediates necessary for amino acid synthesis and energy homeostasis. IDH3A is located in the mitochondrion, where IDH3A forms a heterooligomeric complex with subunits β and γ in a 2:1:1 ratio, and IDH3A activity is allosterically activated by ADP, which lowers the Km for isocitrate, enhancing catalytic efficiency under conditions of increased energy demand.