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Microwave Hall mobility measurements on heavy beef heart mitochondria (1973)

Eley, D. D. ; Mayer, R. J. ; Pethig, R.

Springer

Journal of bioenergetics and biomembranes 4 (1973), S. 187-200

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ISSN: 1573-6881

Source: Springer Online Journal Archives 1860-2000

Topics: Biology , Chemistry and Pharmacology , Physics

Notes: Abstract The observed initial microwave Hall mobility values at 1·21 tesla of heavy beef heart mitochondria is at least six times greater than that observed for bovine serum albumin at similar resistivity values. The respiratory inhibitor cyanide significantly reduces the initial Hall mobility values for HBHM and for a preparation of HBHM cytochrome oxidase. The four enzymic complexes of the respiratory chain were partially or completely separated. Of these complexes cytochrome oxidase exhibits the largest microwave Hall mobility. The maximum hydration content of loosely bound water for freezedried preparations of cytochrome oxidase is 5% by weight; 60% of this hydration content is driven off by microwave power. Since the effective ac resistivity of the samples of cytochrome oxidase did not appreciably vary with changes in hydration content, the true resistivity of cytochrome oxidase has a value of the order 5×103 ohm cm and possibly much lower. The electron transport pathway (as measured by Hall signal) of cytochrome oxidase is irreversibly damaged by prolonged exposure to microwave irradiation at 9·2 GHz. This is accompanied by the complete loss of capacity to oxidise ferrocytochromec. Such changes do not occur with HBHM or with the other respiratory complexes. There appears to be a direct relationship between observed Hall signals and the capacity of cytochrome oxidase to oxidize ferrocytochromec. There is a “background” signal which is not directly related to electron transport but which is dependent on the conformation of the cytochrome oxidase. The observed electronic parameters of cytochrome oxidase do not depend appreciably on its redox state. Acid denaturation of cytochrome oxidase drastically reduces the Hall signal, to include almost complete removal of the “background” signal. It also more than doubles ac resistivity. An electron tunnelling model is outlined.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1007/BF01516056

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1-Hydroxy-2-phenylazo-anthracene aus 1,2-Anthrachinon und Arylhydrazinen (1973)

Morgenstern, J. ; Tontscheff, N. ; Mayer, R.

New York, NY : Wiley-Blackwell

Journal für Praktische Chemie/Chemiker-Zeitung 315 (1973), S. 1099-1104

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ISSN: 0021-8383

Keywords: Chemistry ; Organic Chemistry

Source: Wiley InterScience Backfile Collection 1832-2000

Topics: Chemistry and Pharmacology

Notes: Die bisher unbekannten 1-Hydroxy-2-phenylazo-anthracene 1 sind in guten Ausbeuten durch Kondensation von 1,2-Anthrachinon mit Arylhydrazinen zu erhalten. Die isomeren 1-Phenylazo-2-hydroxy-anthracene 5 lassen sich in Anlehnung an die Literatur durch Kupplung diazotierter Arylamine auf 2-Hydroxy-anthracen synthetisieren. Die Typen 1 absorbieren in Cyclohexan und DMF etwas längerwellig als die isomeren 5 und sind in DMF polarographisch insgesamt etwas leichter reduzierbar.

Additional Material: 1 Tab.