P41565
uniprot
P41565
canonical
activity_regulation
ACTIVITY REGULATION: The heterotetramer and the heterodimer composed of IDH3A and IDH3G subunits can be allosterically activated by citrate (CIT) or/and ADP, and the two activators can act independently or synergistically. The heterodimer composed of IDH3A and IDH3B subunits cannot be allosterically regulated and the allosteric regulation of the heterotetramer is through the IDH3G subunit and not the IDH3B subunit. The IDH3G subunit contains the allosteric site which consists of a CIT-binding site and an ADP-binding site, and the binding of CIT and ADP causes conformational changes at the allosteric site which are transmitted to the active site in the catalytic subunit (IDH3A) through a cascade of conformational changes at the heterodimer interface, leading to stabilization of the isocitrate-binding at the active site and thus activation of the enzyme. ATP can activate the heterotetramer and the heterodimer composed of IDH3A and IDH3G subunits at low concentrations but inhibits their activities at high concentrations, whereas ATP exhibits only inhibitory effect on the heterodimer composed of IDH3A and IDH3B subunits. {ECO:0000250|UniProtKB:P51553}.
uniprot
proteins
amino_acid_sequence
MALKVAIAAGSAAKAIFKPALLCRPWEVLAAHEAPRRSISSQQTIPPSAKYGGRHTVTMIPGDGIGPELMLHVKSVFRHACVPVDFEEVHVSSNADEEDIRNAIMAIRRNRVALKGNIETNHDLPPSHKSRNNILRTSLDLYANVIHCKSLPGVVTRHKDIDILIVRENTEGEYSSLEHESVAGVVESLKIITKAKSLRIAEYAFKLAQESGRKKVTAVHKANIMKLGDGLFLQCCREVAARYPQITFDSMIVDNTTMQLVSRPQQFDVMVMPNLYGNIVNNVCAGLVGGPGLVAGANYGHVYAVFETATRNTGKSIANKNIANPTATLLASCMMLDHLKLHSYATSIRKAVLASMDNENMHTPDIGGQGTTSQAIQDIIRHIRIINGRAVEA
uniprot
proteins
function
FUNCTION: Regulatory subunit which plays a role in the allosteric regulation of the enzyme catalyzing the decarboxylation of isocitrate (ICT) into alpha-ketoglutarate. The heterodimer composed of the alpha (IDH3A) and beta (IDH3B) subunits and the heterodimer composed of the alpha (IDH3A) and gamma (IDH3G) subunits, have considerable basal activity but the full activity of the heterotetramer (containing two subunits of IDH3A, one of IDH3B and one of IDH3G) requires the assembly and cooperative function of both heterodimers. {ECO:0000250|UniProtKB:P51553}.
uniprot
proteins
mass_dalton
42851
uniprot
proteins
protein_family
Isocitrate and isopropylmalate dehydrogenases family
uniprot
proteins
pubmed
22673903
uniprot
proteins
pubmed
8240232
uniprot
proteins
pubmed
9286695
uniprot
proteins
sequence_length
393
uniprot
proteins
subcellular_location
SUBCELLULAR LOCATION: Mitochondrion {ECO:0000250|UniProtKB:P51553}. Photoreceptor inner segment {ECO:0000250|UniProtKB:P51553}.
uniprot
proteins