Konstantinov A, Vygodina T, Popova E, Berka V, Musatov A. Spectral shifts of cytochrome c oxidase induced by complexons.
FEBS Lett 1989;
245:39-42. [PMID:
2538363 DOI:
10.1016/0014-5793(89)80187-5]
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Abstract
Ca2+-chelating agents, such as EDTA and ATP, are shown to bring about a rapid spectral response of the oxidized cytochrome c oxidase due to reversal of the Ca2+-induced red shift of the gamma- and alpha-absorption bands of the ferric enzyme. In addition, complexons are found to bring about Ca2+-independent, slow irreversible spectral changes indicative of a conformational transition of cytochrome oxidase. 1 mol EDTA per mol enzyme is sufficient to produce the maximal effect even in the presence of excess Ca2+, indicating high specificity of interaction. It is suggested that the conformation of cytochrome c oxidase may be regulated by the tightly bound "non-redox' metal ions (Mg, Zn, Cux) known to be present in the enzyme. These ions might be involved in specific binding of physiological effectors with chelating properties, such as ATP.
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