Dihydrolipoamide dehydrogenase

Dihydrolipoamide dehydrogenase

Structure of dihydrolipoamide dehydrogenase

Dihydrolipoamide dehydrogenase (DLD) is an essential enzyme involved in the metabolism of carbohydrates and fatty acids. It plays a crucial role in the process of energy production within cells. DLD is a member of the pyridine nucleotide-disulfide oxidoreductase family and is found in various organisms, including humans.

Structure

DLD is a homodimeric enzyme, meaning it consists of two identical subunits. Each subunit contains three distinct domains: the N-terminal domain, the central domain, and the C-terminal domain. The N-terminal domain contains the active site, where the catalytic reaction takes place. The central domain acts as a linker between the N-terminal and C-terminal domains, while the C-terminal domain is responsible for the dimerization of the enzyme.

Function

DLD plays a critical role in the process of cellular respiration. It is a key component of the pyruvate dehydrogenase complex (PDC), which is responsible for converting pyruvate, a product of glycolysis, into acetyl-CoA. Acetyl-CoA is further utilized in the citric acid cycle to generate ATP, the main energy currency of the cell.

DLD acts as a catalyst in the transfer of electrons from dihydrolipoamide, a coenzyme, to NAD+, a coenzyme. This transfer of electrons is essential for the regeneration of the active form of lipoamide, which is required for the continuous functioning of the PDC. DLD also plays a role in the metabolism of other alpha-keto acids, such as alpha-ketoglutarate and branched-chain alpha-keto acids.

Clinical Significance

Mutations in the gene encoding DLD can lead to a rare genetic disorder known as dihydrolipoamide dehydrogenase deficiency. This condition is characterized by a deficiency in DLD activity, resulting in impaired energy production and the accumulation of toxic metabolites. Symptoms of this disorder can vary widely and may include developmental delay, neurological abnormalities, muscle weakness, and lactic acidosis.

See Also

• Pyruvate dehydrogenase complex
• Citric acid cycle
• Glycolysis

External Links

• Dihydrolipoamide dehydrogenase gene on NCBI
• Dihydrolipoamide dehydrogenase entry on UniProt