Dehydrogenases

Definition

Dehydrogenases are a class of enzymes that catalyze the removal of hydrogen from a substrate, facilitating redox reactions in which electrons are transferred. These enzymes play a crucial role in cellular metabolism, particularly in the oxidation of organic molecules and the reduction of electron carriers, contributing to energy production and various biosynthetic processes.

5 Must Know Facts For Your Next Test

1. Dehydrogenases can be specific for certain substrates, with examples including alcohol dehydrogenase, lactate dehydrogenase, and glucose-6-phosphate dehydrogenase.
2. These enzymes are crucial in cellular respiration, particularly in glycolysis and the citric acid cycle, where they help convert energy stored in nutrients into usable forms.
3. The reduction of NAD+ to NADH by dehydrogenases is essential for ATP production in oxidative phosphorylation.
4. Dehydrogenases can be influenced by factors such as pH, temperature, and the concentration of substrates or products, which can affect their activity.
5. Some dehydrogenases are involved in detoxification processes by converting harmful substances into less toxic forms through redox reactions.

Review Questions

• How do dehydrogenases facilitate redox reactions in metabolism?
  • Dehydrogenases facilitate redox reactions by removing hydrogen atoms from substrates and transferring them to electron carriers like NAD+ or FAD. This process not only oxidizes the substrate but also reduces the coenzyme, enabling the conversion of energy stored in organic molecules into forms that cells can use. This essential function highlights the role of dehydrogenases in metabolic pathways that produce ATP and other important biomolecules.
• Discuss the role of dehydrogenases in glycolysis and how their function impacts cellular energy production.
  • In glycolysis, dehydrogenases play a key role by catalyzing reactions that convert glucose into pyruvate while producing NADH. For example, glyceraldehyde-3-phosphate dehydrogenase facilitates the oxidation of glyceraldehyde-3-phosphate, generating NADH and contributing to the overall yield of ATP during anaerobic and aerobic respiration. This function is crucial because NADH will later donate electrons to the electron transport chain, significantly impacting cellular energy production.
• Evaluate how abnormalities in dehydrogenase activity can affect metabolic pathways and overall health.
  • Abnormalities in dehydrogenase activity can lead to disruptions in critical metabolic pathways, resulting in various health issues. For instance, deficiencies in lactate dehydrogenase can cause impaired lactic acid metabolism, leading to muscle fatigue and other complications. Additionally, alcohol dehydrogenase deficiencies can increase susceptibility to alcohol toxicity, highlighting how proper enzyme function is vital for maintaining metabolic balance and preventing diseases linked to metabolic dysregulation.

Related terms

Oxidation: The process involving the loss of electrons or hydrogen from a molecule, often coupled with the gain of oxygen.

Reduction: The process that involves the gain of electrons or hydrogen by a molecule, often coupled with the loss of oxygen.

NAD+/NADH: Nicotinamide adenine dinucleotide (NAD+) is an important electron carrier that is reduced to NADH during metabolic reactions, playing a key role in redox biology.