dehydrogeneras

Dehydrogenases are enzymes that catalyze oxidation-reduction (redox) reactions in which one or more hydrogen atoms are removed from a substrate. In most cases, the removed electrons are transferred to a suitable electron acceptor, most commonly the nicotinamide adenine dinucleotide cofactors NAD+ or NADP+, or to flavin cofactors such as FAD or FMN. Because of this reliance on these cofactors, dehydrogenases are typically members of the oxidoreductase (EC 1) family of enzymes.

Their reactions are usually reversible, allowing cells to balance oxidation and reduction states. Many dehydrogenases participate in central metabolic pathways, including glycolysis, the citric acid cycle, the pentose phosphate pathway, and amino acid metabolism. They can act on various substrates, from alcohols and aldehydes to sugars and organic acids, and their activity is often regulated by cellular energy status and cofactor availability.

Examples include lactate dehydrogenase, which converts lactate to pyruvate using NAD+, and alcohol dehydrogenase, which oxidizes alcohols to aldehydes or ketones. Other well-known dehydrogenases include malate dehydrogenase, glucose-6-phosphate dehydrogenase, and succinate dehydrogenase, the latter also functioning in the mitochondrial electron transport chain. The naming tradition reflects the substrate and the electron acceptor, rather than a single fixed direction of reaction.

Any dysfunction in dehydrogenases can disrupt energy production or redox balance and is implicated in diseases or metabolic disorders. For example, LDH levels are used in clinical diagnostics to assess tissue damage, while glucose-6-phosphate dehydrogenase deficiency affects redox homeostasis in red blood cells.