1,3-bisphosphoglycerate

Definition

1,3-bisphosphoglycerate is an important intermediate in the glycolytic pathway, formed from the conversion of glyceraldehyde-3-phosphate. This molecule plays a crucial role in energy metabolism as it contains high-energy acyl phosphate bonds that can be harnessed to generate ATP. Its formation marks a key step in the conversion of glucose into pyruvate, linking glycolysis to the citric acid cycle through the production of reducing equivalents.

5 Must Know Facts For Your Next Test

1. 1,3-bisphosphoglycerate is formed during glycolysis when glyceraldehyde-3-phosphate is phosphorylated by inorganic phosphate.
2. This compound has a high-energy acyl phosphate bond, which is crucial for substrate-level phosphorylation that leads to ATP production.
3. In glycolysis, 1,3-bisphosphoglycerate donates a phosphate group to ADP, forming ATP and converting it to 3-phosphoglycerate.
4. The conversion of 1,3-bisphosphoglycerate is catalyzed by the enzyme phosphoglycerate kinase.
5. 1,3-bisphosphoglycerate is also a precursor for the synthesis of 2,3-bisphosphoglycerate, which regulates oxygen release from hemoglobin.

Review Questions

• How does 1,3-bisphosphoglycerate contribute to ATP production during glycolysis?
  • 1,3-bisphosphoglycerate contributes to ATP production during glycolysis through a process called substrate-level phosphorylation. This occurs when 1,3-bisphosphoglycerate donates a phosphate group to ADP via the action of the enzyme phosphoglycerate kinase. The reaction produces ATP and transforms 1,3-bisphosphoglycerate into 3-phosphoglycerate. This step is crucial because it represents one of the few instances where ATP is generated directly in glycolysis.
• Discuss the significance of 1,3-bisphosphoglycerate in linking glycolysis to the citric acid cycle.
  • 1,3-bisphosphoglycerate serves as a critical intermediate in glycolysis that connects energy metabolism with subsequent pathways such as the citric acid cycle. After glycolysis converts glucose into pyruvate, pyruvate can be transformed into acetyl-CoA, which enters the citric acid cycle. The formation of 1,3-bisphosphoglycerate signifies an essential energy-rich compound that not only contributes to ATP generation but also influences the overall metabolic flow toward further energy extraction in cellular respiration.
• Evaluate how variations in the concentration of 1,3-bisphosphoglycerate can impact cellular respiration and energy metabolism.
  • Variations in the concentration of 1,3-bisphosphoglycerate can significantly impact cellular respiration and energy metabolism by influencing the rate of glycolysis and ATP production. Higher levels of this compound could enhance ATP generation through substrate-level phosphorylation, promoting efficient energy transfer within cells. Conversely, lower concentrations may slow down glycolysis and reduce ATP output, potentially leading to an energy deficit. Moreover, fluctuations in its levels can affect downstream processes such as 2,3-bisphosphoglycerate synthesis, which is crucial for regulating oxygen delivery in tissues. Thus, maintaining optimal levels of 1,3-bisphosphoglycerate is vital for balanced cellular energy metabolism.

Related terms

Glycolysis: A metabolic pathway that converts glucose into pyruvate, producing ATP and NADH in the process.

ATP:

A high-energy molecule that serves as the primary energy currency in cells, produced during glycolysis and the citric acid cycle.

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.