Open AccessLack of oxygen sensing by mitochondria in platelets
Author(s) -
Arthur Peter G,
Ngo CamTu,
Moretta Paul,
Guppy Michael
Publication year - 1999
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1046/j.1432-1327.1999.00846.x
Subject(s) - oxygen , cytochrome c oxidase , mitochondrion , cytochrome c , chemistry , cytochrome , biochemistry , platelet , biophysics , limiting oxygen concentration , biology , enzyme , immunology , organic chemistry
The range over which cells are sensitive to changes in oxygen concentration remains uncertain. Wilson and colleagues [Wilson, D.F. (1994) Med. Sci. Sports Exerc. 26 , 37–43] have suggested that cytochrome oxidase is sensitive to oxygen concentrations below about 40 µ m , but proposed that this sensitivity is obscured in intact cells because an increase in reduction state of cytochrome c acts to maintain oxygen consumption. We have tested this hypothesis in platelets, which are small cells (2–4 µm diameter, < 0.5 µm thick) that do not decrease their rate of oxygen consumption until oxygen concentrations fall below 2.5 µ m . Contrary to the expectations of the hypothesis, the reduction state of cytochrome c , the concentration of NADH and the rate of glycolytic output are not changed as oxygen concentration declines from 40 µ m down to 5 µ m . Therefore, we conclude that at least some cell types contain mitochondria that are not capable of sensing oxygen above 5 µ m by the mechanism proposed by Wilson and colleagues.