J. Biochem, 1968, Vol. 63, No. 2 219-225
© 1968 Japanese Biochemical Society
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Oxidative Phosphorylation in Micrococcus denitrificans
V. Effects of Iron Deficiency on Respiratory Components and Oxidative Phosphorylation *
Institute for Protein Research, Osaka University Kita-ku, Osaka
** Present address: Institute for Enzyme Research, School of Medicine, Tokushima University, Tokushima.
Membrane fragments prepared from Micrococcus denitrificans grown aerobically in an iron-sufficient medium showed an ESR signal at g=1.94 on reduction with NADH, but not with succinate. From the properties of this signal, it was concluded that the NADH dehydrogenase region of the respiratory chain of such preparations contained a non-heme iron similar to that occurring in mammalian mitochondria.
The signal at g=1.94 was greatly reduced or hardly detectable in membrane fragments prepared from cells grown in an iron-deficient medium (<0.05 µg Fe/ml). The contents of iron and cytochromes in such deficient preparations were decreased to about 15% and 60%, respectively, of those in normal preparations.
However, the activities of NADH oxidase and oxidative phosphorylation of the deficient preparations were practically the same with those observed in the normal preparation. The NADH oxidation by the deficient preparation was also sensitive to o-phenanthroline.
* This investigation was supported in part by grant from the National Institute of Health, U.S. Public Health Service (TW 00254-01).