Energy Harvesting Flashcards
ATPase
ATPases (EC 3.6.1.3, Adenosine 5’-TriPhosphatase, adenylpyrophosphatase, ATP monophosphatase, triphosphatase, SV40 T-antigen, ATP hydrolase, complex V (mitochondrial electron transport - F-ATPase), (Ca2+ + Mg2+)-ATPase, HCO3−-ATPase, adenosine triphosphatase) are a class of enzymes that catalyze the decomposition of ATP into ADP and a free phosphate ion or the inverse reaction. This dephosphorylation reaction releases energy, which the enzyme (in most cases) harnesses to drive other chemical reactions that would not otherwise occur. This process is widely used in all known forms of life.
F-ATPase, also known as F-Type ATPase, is an ATPase/synthase found in bacterial plasma membranes, in mitochondrial inner membranes (in oxidative phosphorylation, where it is known as Complex V), and in chloroplast thylakoid membranes. It uses a proton gradient to drive ATP synthesis by allowing the passive flux of protons across the membrane down their electrochemical gradient and using the energy released by the transport reaction to release newly formed ATP from the active site of F-ATPase. Together with V-ATPases and A-ATPases, F-ATPases belong to superfamily of related rotary ATPases.
F-ATPase consists of two domains:
1) the Fo domain, which is integral in the membrane and is composed of 3 different types of integral proteins classified as a, b and c.[1]
2) the F1, which is peripheral (on the side of the membrane that the protons are moving into). F1 is composed of 5 polypeptide units α3β3γδε that bind to the surface of the Fo domain.[1]
F-ATPases usually work as ATP synthases instead of ATPases in cellular environments. That is to say, it usually makes ATP from the proton gradient instead of working in the other direction like V-ATPases typically do. They do occasionally revert as ATPases in bacteria.
Activites of the inner mitochondrial membrane (IMM)
- NADH/FADH provide electrons to power proton pump which moves protons to outer membrane area (e.g. intermembrane space) and builds up proton gradient. This process is call electron transport
- Protons reenter mitochondrial matrix via a protein complex embedded in the IMM called ATP synthase. This process is called oxidative phosporylation.
Why are phosphates high energy molecules?
Phosphates, particularly in molecules like ATP (Adenosine Triphosphate), contain a lot of energy because of the strong electrostatic repulsion between their negatively charged phosphate groups, which are clustered closely together; when a phosphate group is cleaved off, this repulsion is relieved, releasing a significant amount of energy that can be used by the cell for various processes. [1, 2, 3, 4, 5]
Key points about phosphate energy storage: [1, 2, 3]
• Negative charge repulsion: Each phosphate group carries a negative charge, and when multiple phosphate groups are linked together, their negative charges repel each other, creating a high-energy state. [1, 2, 3]
• Breaking the bond releases energy: When a phosphate group is cleaved off (hydrolyzed), the repulsion between the remaining phosphate groups is reduced, releasing energy. [1, 2, 3]
• Phosphoanhydride bonds: The bonds between phosphate groups in ATP are called phosphoanhydride bonds, which are considered “high-energy” bonds due to the factors mentioned above. [1, 4, 6]
Generative AI is experimental.
[1]https://www.ncbi.nlm.nih.gov/books/NBK553175/[2]https://homework.study.com/explanation/why-does-the-breakage-of-the-last-phosphate-group-in-atp-after-the-first-three-have-been-broken-produce-less-energy.html[3]https://brainly.com/question/38593328[4]https://chem.libretexts.org/Bookshelves/Biological_Chemistry/Supplemental_Modules_(Biological_Chemistry)/Metabolism/Important_High_Energy_Molecules_in_Metabolism[5]https://bodell.mtchs.org/OnlineBio/BIOCD/text/chapter7/concept7.3.html[6]https://en.wikipedia.org/wiki/High-energy_phosphate
