Dihydrolipoamide dehydrogenase (DLD)

Dihydrolipoamide dehydrogenase is a highly conserved, flavin-dependent mitochondrial enzyme essential for energy metabolism in eukaryotic cells[4][5][1]. As the E3 subunit of several multi-enzyme complexes (including pyruvate dehydrogenase, α-ketoglutarate dehydrogenase, branched-chain α-keto acid dehydrogenase, and the glycine cleavage system), it catalyzes the oxidation of dihydrolipoamide to lipoamide, concurrently reducing NAD+ to NADH[1][3][4]. Structurally, the enzyme is a homodimer, each monomer containing an FAD and NAD+ binding domain critical for catalysis[1][7]. It also possesses moonlighting functions, including redox regulation, DNA and metal binding, and even serine protease activity under specific pathological conditions[1][5]. DLD dysfunction is associated with neurodegenerative and metabolic diseases, cancer, and oxidative stress-related tissue injury. The DLD gene is a key genetic locus for diagnosing hereditary mitochondrial disorders. Several drugs target DLD, most notably in the context of cancer metabolism and mitochondrial disease therapies.

Other names

lipoamide dehydrogenasedihydrolipoyl dehydrogenaseE3 component (of pyruvate dehydrogenase, α-ketoglutarate dehydrogenase, and branched-chain α-keto acid dehydrogenase complexes)hE3p64k (in Neisseria meningitidis)

Enzyme inhibition (prevents oxidation of dihydrolipoamide, disrupts energy metabolism); Allosteric modulation (drug-induced conformational changes affecting activity); Indirect modulation of oxidative stress and cell death pathways