Plays a role in intermediary metabolism and energy production. It may tightly associate or interact with the pyruvate dehydrogenase complex. D-threo-isocitrate + NADP(+) = 2-oxoglutarate + CO2 + NADPH Binds 1 Mg(2+) or Mn(2+) ion per subunit. Homodimer. Acetylation at Lys-413 dramatically reduces catalytic activity. Deacetylated by SIRT3 (By similarity). On the 2D-gel the determined pI of this protein (spot P8) is: 9.0, its MW is: 42 kDa. Belongs to the isocitrate and isopropylmalate dehydrogenases family.