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Nanomolar concentrations of nitric oxide reversibly inhibit synaptosomal respiration by competing with oxygen at cytochrome oxidase
Author(s) -
Brown Guy C.,
Cooper Chris.E.
Publication year - 1994
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(94)01290-3
Subject(s) - cytochrome c oxidase , oxygen , nitric oxide , chemistry , cytochrome , electron transport complex iv , respiration , oxidase test , cytochrome c , biochemistry , enzyme , mitochondrion , biology , anatomy , organic chemistry
Nitric oxide (NO) reversibly inhibited oxygen consumption of brain synaptosomes. Inhibition was reversible, occurred at the level of cytochrome oxidase, and was apparently competitive with oxygen, with half‐inhibition by 270 nM NO at oxygen concentrations around 145 μM and by 60 nM NO at around 30μM O 2 . Isolated cytochrome oxidase was inhibited by similar levels of NO. These levels of NO are within the measured physiological and pathological range for a number of tissues and conditions, suggesting that NO inhibition of cytochrome oxidase and the competion with oxygen may occur in vivo.