NADH Dehydrogenase

Definition

NADH dehydrogenase is an enzyme that plays a crucial role in cellular respiration by catalyzing the oxidation of NADH to NAD+, transferring electrons to the electron transport chain. This enzyme helps facilitate the production of ATP, the energy currency of the cell, through the process of oxidative phosphorylation. By converting NADH back to NAD+, it enables the continuation of glycolysis and the citric acid cycle, linking carbohydrate metabolism and energy production.

5 Must Know Facts For Your Next Test

1. NADH dehydrogenase is also known as Complex I in the electron transport chain, making it one of the first enzymes to act during cellular respiration.
2. This enzyme is essential for regenerating NAD+, which is necessary for glycolysis and the citric acid cycle to continue functioning.
3. Inhibition or malfunction of NADH dehydrogenase can lead to a decrease in ATP production, affecting overall cellular energy levels.
4. NADH dehydrogenase contains several prosthetic groups, including flavin mononucleotide (FMN) and iron-sulfur clusters, which are critical for its function.
5. The transfer of electrons facilitated by NADH dehydrogenase contributes to creating a proton gradient across the inner mitochondrial membrane, which is vital for ATP synthesis.

Review Questions

• How does NADH dehydrogenase contribute to ATP production in cells?
  • NADH dehydrogenase contributes to ATP production by oxidizing NADH to NAD+, which releases electrons that are then passed along the electron transport chain. This transfer of electrons helps create a proton gradient across the inner mitochondrial membrane, ultimately driving ATP synthesis through oxidative phosphorylation. By replenishing NAD+, this enzyme ensures that essential metabolic pathways like glycolysis and the citric acid cycle can continue, maintaining cellular energy levels.
• What would be the consequences of impaired function of NADH dehydrogenase on cellular metabolism?
  • Impaired function of NADH dehydrogenase would lead to reduced conversion of NADH back to NAD+, causing a shortage of available NAD+ for critical metabolic processes like glycolysis and the citric acid cycle. This would result in decreased ATP production due to less efficient operation of the electron transport chain. The overall energy metabolism would be compromised, leading to reduced cellular function and potential cell death if not remedied.
• Evaluate the significance of NADH dehydrogenase in both aerobic respiration and its potential implications in metabolic diseases.
  • NADH dehydrogenase is pivotal in aerobic respiration as it initiates the electron transport chain, crucial for ATP generation in aerobic organisms. Its dysfunction can lead to various metabolic diseases due to inadequate energy production and accumulation of toxic metabolites. Research has shown that mutations or deficiencies in this enzyme can contribute to conditions such as neurodegenerative diseases and mitochondrial disorders, highlighting its importance not only in normal metabolism but also in disease pathology.

Related terms

Electron Transport Chain: A series of protein complexes located in the inner mitochondrial membrane that transfers electrons from NADH and FADH2 to oxygen, resulting in ATP production.

Oxidative Phosphorylation: The metabolic pathway where ATP is produced as electrons are transferred through the electron transport chain and combined with oxygen to form water.

Citric Acid Cycle: A series of chemical reactions used by all aerobic organisms to generate energy through the oxidation of acetyl-CoA derived from carbohydrates, fats, and proteins.