what’s the main role of TCA cycle in the body
Oxidation of 2-C acetyl group in acetyl CoA to 2CO2
Equation of Krebs cycle
Acetyl CoA + 3NAD+ + FAD + GDP + Pi + H2O
—>
2CO2 + 3NADH + FADH2 + GTP + CoASH + 3H+
How many ATP are produced in one turn of TCA cycle?
12 ATP
1GTP= 1ATP
3NADH= 9ATP
FADH2= 2ATP
Why is TCA amphibolic?
- Catabolic because oxidation of acetyl CoA to CO2 & energy is conserved in coenzyme molecules
- Anabolic because many intermediates of TCA cycle are precursors for biosynthetic pathways
Oxaloacetate Is precursor in which biosynthetic pathway
Gluconeogenesis & amino acid synthesis
Ketoglutarate Is precursor in which biosynthetic pathway
Amino acid synthesis
Succinyl CoA Is precursor in which biosynthetic pathway
Synthesis of heme
Acetyl CoA Is precursor in which biosynthetic pathway
It’s converted to citrate for synthesis of cholesterol
What are anaplerotic reactions?
Reactions that are required to replenish the intermediates of TCA cycle as they get depleted in the synthetic reactions
Anapleurotic reaction: oxaloacetate
- Pyruvate carboxylases catalyzes the production of oxaloacetate
- transamimation and deamimation
Anapleurotic reaction: alpha ketoglutarate
Transamination & deamination
Anapleurotic reaction: Succinyl Coa
- Oxidation of odd fatty acid
- Breakdown of isoleucine, methionine, valine
What are 3 enzymes that regulate TCA cycle?
What are their inhibitors?
- Citrate synthase
- ATP, NADH, Succinyl CoA - Isocitrate dehydrogenase
- ATP, NADH - Alpha-ketoglutarate dehydrogenase
- NADH, Succinyl coA
What are the activators of isocitrate dehydrogenase
ADP, Ca2+
Which biological metabolic pathway provides an intermediate for protein and nucleotide synthesis, and also participates in making ketoacids for non essential amino acids?
TCA cycle
