The uncoupler dinitrophenol (DNP) prevents ATP synthesis while allowing electron
ID: 181018 • Letter: T
Question
The uncoupler dinitrophenol (DNP) prevents ATP synthesis while allowing electron transport to proceed because DNP is capable of transporting protons across the membrane, dissipating the proton gradient. DNP prevents the buildup of a proton gradient by altering the electron transfer complexes such that they no longer pump protons. DNP binds to the ATP synthase and acts as an inhibitor of the enzyme. DNP transports protons out of the mitochondria after they are pumped out of the matrix. The uncoupler dinitrophenol (DNP) prevents ATP synthesis while allowing electron transport to proceed because DNP is capable of transporting protons across the membrane, dissipating the proton gradient. DNP prevents the buildup of a proton gradient by altering the electron transfer complexes such that they no longer pump protons. DNP binds to the ATP synthase and acts as an inhibitor of the enzyme. DNP transports protons out of the mitochondria after they are pumped out of the matrix.Explanation / Answer
The uncoupler, 2,4-dinitrophenol (DNP) is a small lipophilic molecule and the uncoupling action of DNP is due to the fact that both the phenol and the corresponding phenolate ion are significantly soluble in the lipid core of the inner mitochondrial membrane. The phenol diffuses through the core toward the matrix, where it loses a proton; the phenolate ion then diffuses back toward the cytosol side, where it picks up a proton to repeat the process.
DNP acts as a proton ionophore, an agent that can transport hydrogen cations or protons across biological membranes. It dissipates the proton gradient across mitochondrial membranes, collapsing the proton motive force that the cell uses to generate mainly of its ATP chemical energy. Instead of producing ATP, the energy of the proton gradient is lost as heat.
Hence, the correct answer is the option(a)
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