Oxoglutarate dehydrogenase (lipoamide) (OGDH)

The alpha-ketoglutarate dehydrogenase complex (KGDHC) is a crucial mitochondrial multienzyme assembly responsible for the oxidative decarboxylation of alpha-ketoglutarate to succinyl-CoA within the tricarboxylic acid (TCA) cycle [1]. The thiamine pyrophosphate (TPP) site is specifically located on the E1 subunit, also known as oxoglutarate dehydrogenase, which acts as the rate-limiting step of the entire complex [5]. This site requires TPP, a derivative of Vitamin B1, to stabilize the carbanion intermediate during the decarboxylation process [4]. Clinically, reduced activity at this site is a hallmark of neurodegenerative conditions such as Alzheimer’s and Parkinson’s diseases, contributing to impaired cerebral glucose metabolism and increased oxidative stress [3]. Conversely, the complex is a target in oncology, where inhibitors are explored to disrupt the metabolic adaptations of cancer cells [2]. Therapeutic interventions often involve thiamine supplementation or the use of synthetic derivatives like benfotiamine to enhance enzymatic flux in deficiency states [2]. [1] UniProt P36957; [2] StatPearls, Thiamine Deficiency; [3] PubMed PMID: 10896601; [4] PubChem CID 1132; [5] Journal of Biological Chemistry, KGDHC Mechanism.

Other names

Alpha-ketoglutarate dehydrogenase2-oxoglutarate dehydrogenaseE1 subunit of the alpha-ketoglutarate dehydrogenase complexKGDHOGDC

Cofactor supplementation or competitive inhibition at the thiamine pyrophosphate (TPP) binding site to modulate the rate-limiting oxidative decarboxylation of alpha-ketoglutarate.