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[20] Regulation of mitochondrial respiration by adenosine diphosphate, oxygen, and nitric oxide

1999; Academic Press; Linguagem: Inglês

10.1016/s0076-6879(99)01082-4

1557-7988

Alberto Boveris, Lidia E. Costa, Enrique Cadenas, Juan José Poderoso,

Cardiac Ischemia and Reperfusion

This chapter discusses the regulation of mitochondrial respiration by adenosine diphosphate, oxygen, and nitric oxide (NO). Oxygen is required in adequate steady-state concentrations to sustain mitochondrial respiration and ATP production. The reaction of reduced cytochrome oxidase, the oxygen acceptor, and terminal enzyme of the mitochondrial respiratory chain, with O2 is very and fast the rate of electron transfer to cytochrome oxidase by the respiratory chain is the key factor to define the operational O2 concentration for half-maximal rate of O2 uptake. The intracellular oxygen concentration in mammalian organs and tissues, in the 5–25/μM O2 range, is close and partially overlaps with the critical concentration, in the 2–6/μM O2 range, that limits the rate of mitochondrial respiration. Nitric oxide, the product of the NO synthase of vascular endothelium, with estimated steady state concentrations in mammalian tissues in the 0.05–1/μM NO range has been recognized as a high affinity inhibitor of cytochrome oxidase activity and mitochondrial respiration in a competitive way with O2.