NADH

Definition

NADH, or nicotinamide adenine dinucleotide, is a coenzyme that plays a crucial role in numerous metabolic processes within the body. It is the reduced form of NAD+, an important electron carrier that is involved in oxidation-reduction reactions throughout the cell's energy-producing pathways.

5 Must Know Facts For Your Next Test

1. NADH is a key cofactor in the oxidation of alcohols, providing the necessary reducing power for the conversion of alcohols to aldehydes or ketones.
2. In biological reductions, NADH acts as a reducing agent, donating its electrons to various enzymes and substrates to drive important metabolic reactions.
3. During the catabolism of triacylglycerols, NADH is produced as a result of the β-oxidation of fatty acids, providing energy for the cell.
4. NADH is a crucial electron donor in the glycolysis pathway, where it is oxidized to NAD+ to maintain the redox balance and continue the energy-producing process.
5. The conversion of pyruvate to acetyl-CoA, a key step in cellular respiration, involves the oxidation of NADH to NAD+, which is then used in the citric acid cycle.

Review Questions

• Explain the role of NADH in the oxidation of alcohols.
  • NADH is a key cofactor in the oxidation of alcohols, where it provides the necessary reducing power for the conversion of alcohols to aldehydes or ketones. During this process, NADH is oxidized to NAD+, and the released electrons are used to drive the oxidation reaction, allowing the alcohol to be converted to a more oxidized carbonyl compound.
• Describe the function of NADH in the catabolism of triacylglycerols and the subsequent β-oxidation of fatty acids.
  • During the catabolism of triacylglycerols, NADH is produced as a result of the β-oxidation of fatty acids. This NADH provides the reducing power necessary to drive the electron transport chain, ultimately leading to the production of ATP. The NADH generated in this process is a crucial energy source for the cell, powering various metabolic reactions and maintaining the overall energy balance.
• Analyze the role of NADH in the conversion of pyruvate to acetyl-CoA and its subsequent entry into the citric acid cycle.
  • The conversion of pyruvate to acetyl-CoA, a key step in cellular respiration, involves the oxidation of NADH to NAD+. This oxidation of NADH provides the necessary reducing power to drive the reaction, allowing the pyruvate to be converted into acetyl-CoA, which can then enter the citric acid cycle. The NADH generated in this process is a crucial electron donor, feeding into the electron transport chain and ultimately contributing to the production of ATP through oxidative phosphorylation. The central role of NADH in this metabolic pathway highlights its importance in cellular energy metabolism.

Related terms

NAD+:

Nicotinamide adenine dinucleotide (NAD+) is an oxidized coenzyme that accepts electrons in redox reactions, serving as an important electron carrier in various metabolic pathways.

Oxidation-Reduction Reactions: Oxidation-reduction (redox) reactions involve the transfer of electrons from one molecule (the reducing agent) to another (the oxidizing agent), resulting in a change in the oxidation state of the participating molecules.

Electron Transport Chain:

The electron transport chain is a series of protein complexes located in the inner mitochondrial membrane that facilitate the transfer of electrons, ultimately leading to the production of ATP through the process of oxidative phosphorylation.