Uncouplers and Inhibitors of Oxidative Phosphorylation скачать в хорошем качестве

Uncouplers and Inhibitors of Oxidative Phosphorylation

Uncouplers of oxidative phosphorylation in mitochondria inhibit the coupling between the electron transport and phosphorylation reactions and thus inhibit ATP synthesis without affecting the respiratory chain and ATP synthase (H(+)-ATPase). Inhibitors of Oxidative Phosphorylation The given below is the list of inhibitors in Oxidative Phosphorylation. 1. Oligomycins It is a polypeptide antibiotic is obtained from various species of “Streptomyces” They inhibit the transfer of high-energy phosphate to ADP and also inhibit electron transfers coupled to phosphorylation. The antibiotic is a potent inhibitor to the ATP synthase complex. 2. Rutamycin This antibiotic also inhibits both ETC and oxidative phosphorylation. 3. Atractylate It backs oxidative phosphorylation by compelling with ATP & ADP for a site on the ADP-ATP antiport of the mitochondrial membranes. One of the inhibitors list which blocks the oxidative phosphorylation. 4. Bongkrekate It is a toxin formed by bacteria (Pseudomonas) in a coconut preparation from Java.1 It also blocks the ADP-ATP antiport. Uncouplers of Oxidative Phosphorylation Uncouplers can be defined as A substance that uncouples phosphorylation of ADP from electron transfer. Uncoupling agents are compounds which dissociate the synthesis of ATP from the transport of electrons through the cytochrome system. This means that the electron transport continues to function, leading to oxygen consumption but phosphorylation of ADP is inhibited. 2,4-Dinitrophenol A classic uncoupler of oxidative phosphorylation. The substance carries protons across the inner mitochondria membrane. In the presence of these uncouplers, electron transport from NADH to O2 proceeds normally, but ATP is not formed by the mitochondria. ATP is because the proton motive force across the inner mitochondrial membrane is dissipated. DNA and other uncouplers are very useful in metabolic studies because of their specific effect on outside phosphorylation. 2. Dicoumarol (Vitamin.K analog) Used as an anticoagulant. 3. Calcium Transport of Ca+2 ion into mitochondria can cause uncoupling. Mitochondrial transport of Ca+2 is energetically coupled to oxidative phosphorylation. It is coupled with uptake of pi When calcium is transported into mitochondria, electron transport can proceed but energy is required to pump the4 Ca+2 into the mitochondria. Hence, no energy is stored as ATP. 4. CCCP (Chloro carbonyl cyanide phenyl hydrazone) Most active uncoupler These lipid-soluble substances can carry protons across the inner mitochondrial membrane. 5. Physiological un-couplers Excessive thyroxin hormone EFA deficiency Long-chain FA in brown adipose tissue Unconjugated hyperbilirubinemia 6. Valinomycin This is an example of an Ionophore of oxidative phosphorylation. Produced by a type of streptomyces It is a repeating macrocyclic molecule made up of four kinds of residues (L-lactate, L-Valine, D-hydroxyisovalarate, and D-Valine) taken 3 times. Transports K+ from the cytosol into matrix and H+ from the matrix to the cytosol, thereby decreasing the proton gradient.