Glycerol-3-phosphate dehydrogenase

Definition

Glycerol-3-phosphate dehydrogenase is an enzyme that catalyzes the conversion of dihydroxyacetone phosphate (DHAP) to glycerol-3-phosphate, playing a key role in lipid metabolism and energy production. This enzyme operates in the cytoplasm and mitochondria, highlighting its importance in cellular respiration and the shuttle systems that transport reducing equivalents across mitochondrial membranes.

5 Must Know Facts For Your Next Test

1. Glycerol-3-phosphate dehydrogenase exists in two forms: cytosolic and mitochondrial, reflecting its dual role in both glycolysis and the electron transport chain.
2. The enzyme is crucial for the glycerol-3-phosphate shuttle, which allows the transfer of electrons from NADH in the cytosol into the mitochondria for ATP production.
3. By converting DHAP to glycerol-3-phosphate, this enzyme facilitates lipid synthesis, as glycerol-3-phosphate is a precursor for triglycerides.
4. Dysregulation of glycerol-3-phosphate dehydrogenase can impact metabolic disorders, including obesity and diabetes, by altering lipid metabolism.
5. The activity of glycerol-3-phosphate dehydrogenase is influenced by various factors, including substrate availability and hormonal regulation, affecting overall energy homeostasis.

Review Questions

• How does glycerol-3-phosphate dehydrogenase contribute to cellular metabolism and energy production?
  • Glycerol-3-phosphate dehydrogenase plays a vital role in cellular metabolism by catalyzing the conversion of dihydroxyacetone phosphate to glycerol-3-phosphate. This reaction is essential for both lipid synthesis and energy production, as glycerol-3-phosphate serves as a substrate for triglyceride formation. Additionally, the enzyme is involved in the glycerol-3-phosphate shuttle, which helps transfer reducing equivalents into the mitochondria for ATP generation, linking glycolysis with oxidative phosphorylation.
• Discuss the significance of the glycerol-3-phosphate shuttle and how it relates to glycerol-3-phosphate dehydrogenase's function.
  • The glycerol-3-phosphate shuttle is significant because it enables the transport of reducing equivalents from the cytosolic NADH into the mitochondria, where they can be used for ATP production. Glycerol-3-phosphate dehydrogenase facilitates this process by converting dihydroxyacetone phosphate into glycerol-3-phosphate in the cytosol. This intermediate then enters the mitochondria, where it is oxidized back to DHAP by mitochondrial glycerol-3-phosphate dehydrogenase, regenerating NADH and allowing for effective energy transfer between cellular compartments.
• Evaluate how alterations in glycerol-3-phosphate dehydrogenase activity could impact metabolic health.
  • Alterations in glycerol-3-phosphate dehydrogenase activity can significantly impact metabolic health by disrupting lipid metabolism and energy homeostasis. For instance, increased enzyme activity may lead to excessive lipid accumulation, contributing to obesity and insulin resistance. Conversely, reduced activity can hinder lipid synthesis and impair energy production through decreased NADH levels entering the electron transport chain. Understanding these dynamics provides insights into potential therapeutic targets for managing metabolic disorders like type 2 diabetes and cardiovascular diseases.

Related terms

Dihydroxyacetone phosphate (DHAP): A three-carbon sugar phosphate that acts as an intermediate in glycolysis and can be converted into glycerol-3-phosphate by glycerol-3-phosphate dehydrogenase.

Mitochondrial shuttle: Mechanisms that transport electrons from the cytosol into the mitochondria for oxidative phosphorylation, ensuring efficient energy production.

Glycerol-3-phosphate shuttle: A specific shuttle mechanism that uses glycerol-3-phosphate to transfer reducing equivalents from cytosolic NADH into the mitochondria.