Nicotinamide nucleotide transhydrogenase (NNT) in the inner mitochondrialmembrane catalyzes the reaction NADH + NADP+ → NAD+ + NADPH to generate the NADPH needed for certain reactions that help destroy reactive oxygen species. (a) Explain why the NNT reaction cannot be driven primarily by the diff erence in substrate reduction potentials (Δℰ). (b) In fact, the NNT reaction is driven by proton translocation across the membrane (from outside to inside). How does operation of the transhydrogenase aff ect the effi ciency of oxidative phosphorylation?

Nicotinamide nucleotide transhydrogenase (NNT) in the inner mitochondrialmembrane catalyzes the reaction NADH + NADP+ → NAD+ + NADPH to generate the NADPH needed for certain reactions that help destroy reactive oxygen species. (a) Explain why the NNT reaction cannot be driven primarily by the diff erence in substrate reduction potentials (Δℰ). (b) In fact, the NNT reaction is driven by proton translocation across the membrane (from outside to inside). How does operation of the transhydrogenase aff ect the effi ciency of oxidative phosphorylation?

Biochemistry

6th Edition

ISBN:9781305577206

Author:Reginald H. Garrett, Charles M. Grisham

Publisher:Reginald H. Garrett, Charles M. Grisham

Chapter27: Metabolic Integration And Organ Specialization

Section: Chapter Questions

Problem 4P

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