OGDC-E Protein, Mouse (His-SUMO)

The OGDC-E protein is a component of the 2-oxoglutarate dehydrogenase complex (OGDHC), specifically the E1o component. It plays a crucial role in the first and rate-limiting step of converting 2-oxoglutarate to succinyl-CoA and CO(2) within the OGDHC. This conversion is catalyzed by the entire OGDHC. The OGDC-E protein facilitates the irreversible decarboxylation of 2-oxoglutarate (alpha-ketoglutarate) using the thiamine diphosphate (ThDP) cofactor. It then transfers the decarboxylated acyl intermediate to an oxidized dihydrolipoyl group that is covalently linked to the E2 enzyme (dihydrolipoyllysine-residue succinyltransferase or DLST). This process occurs in the mitochondrion and is a critical step in the Krebs (citric acid) cycle, which is a common pathway for oxidizing fuel molecules such as carbohydrates, fatty acids, and amino acids. While the OGDC-E protein can catalyze the decarboxylation of 2-oxoadipate in vitro, it does so at a much slower rate compared to 2-oxoglutarate. Additionally, a fraction of the 2-oxoglutarate dehydrogenase complex localizes in the nucleus and is involved in lysine succinylation of histones. It associates with KAT2A on chromatin and supplies succinyl-CoA to the histone succinyltransferase KAT2A.