(A) Citrate Partly active carboxylase Inactive carboxylase Citrate (B) Dephosphorylated Highly phosphorylated 5 10 Citrate (mM) FIGURE 22.36 Dependence of the catalytic activity of acetyl CoA carboxylase on the concentration of citrate. (A) Citrate can partly activate the phosphorylated carboxylase. (B) The dephosphorylated form of the carboxylase is highly active even when citrate is absent. Citrate partly overcomes the inhibition produced by phosphorylation. [Information from G. M. Mabrouk, I. M. Helmy, K. G. Thampy, and S. J. Wakil. J. Biol. Chem. 265:6330-6338, 1990.] Acetyl CoA carboxylase activity
Electron Transport Chain
The electron transport chain, also known as the electron transport system, is a group of proteins that transfer electrons through a membrane within mitochondria to create a gradient of protons that drives adenosine triphosphate (ATP)synthesis. The cell uses ATP as an energy source for metabolic processes and cellular functions. ETC involves series of reactions that convert redox energy from NADH (nicotinamide adenine dinucleotide (NAD) + hydrogen (H)) and FADH2(flavin adenine dinucleotide (FAD)) oxidation into proton-motive force(PMF), which is then used to synthesize ATP through conformational changes in the ATP synthase complex, a process known as oxidative phosphorylation.
Metabolism
Picture a campfire. It keeps the body warm on a cold night and provides light. To ensure that the fire keeps burning, fuel needs to be added(pieces of wood in this case). When a small piece is added, the fire burns bright for a bit and then dies down unless more wood is added. But, if too many pieces are placed at a time, the fire escalates and burns for a longer time, without actually burning away all the pieces that have been added. Many of them, especially the larger chunks or damp pieces, remain unburnt.
Cellular Respiration
Cellular respiration is the cellular process involved in the generation of adenosine triphosphate (ATP) molecules from the organic nutritional source obtained from the diet. It is a universal process observed in all types of life forms. The glucose (chemical formula C6H12O6) molecules are the preferred raw material for cell respiration as it possesses a simple structure and is highly efficient in nature.
Figure 22.3 6 shows the response of acetyl CoA carboxylase to varying amounts of citrate. Explain this effect in light of the allosteric effects that citrate has on the enzyme. Predict the effects of increasing concentrations of palmitoyl CoA.
![(A)
Citrate
Partly
active
carboxylase
Inactive
carboxylase
Citrate
(B)
Dephosphorylated
Highly phosphorylated
5
10
Citrate (mM)
FIGURE 22.36 Dependence of the
catalytic activity of acetyl CoA
carboxylase on the concentration of
citrate. (A) Citrate can partly activate the
phosphorylated carboxylase. (B) The
dephosphorylated form of the carboxylase
is highly active even when citrate is absent.
Citrate partly overcomes the inhibition
produced by phosphorylation. [Information
from G. M. Mabrouk, I. M. Helmy,
K. G. Thampy, and S. J. Wakil. J. Biol.
Chem. 265:6330-6338, 1990.]
Acetyl CoA carboxylase activity](/v2/_next/image?url=https%3A%2F%2Fcontent.bartleby.com%2Fqna-images%2Fquestion%2Fac13e902-d9f9-42e4-b498-a84d5e52a65f%2Fa354eebb-b3c4-4fbd-b3dd-442cb4e3504e%2Fmwq9x2_processed.png&w=3840&q=75)
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