scholarly journals Oxygen kinetics of frozen cytochrome oxidase. The capacity of the oxygen pocket

1980 ◽  
Vol 185 (2) ◽  
pp. 527-530 ◽  
Author(s):  
K De Fonseka ◽  
B Chance
Keyword(s):  
Low Temperature ◽  
Cytochrome Oxidase ◽  
Limited Capacity ◽  
Oxygen Kinetics ◽  
Membrane Bound ◽  
Low Temperature Kinetics ◽  
The Difference ◽  
Kinetics Of

Low-temperature kinetics of the reaction between O2 and cytochrome oxidase suggest the existence of an O2 pocket of limited capacity in membrane-bound cytochrome oxidase, and one of larger capacity in purified cytochrome oxidase. A model is proposed to explain the difference in capacity of the pockets.

scholarly journals Low-temperature kinetics of the reactions of fully reduced membrane-bound cytochrome oxidase with oxygen in the Soret, α and near-infrared regions

1979 ◽  
Vol 177 (2) ◽  
pp. 613-621 ◽  
Author(s):  
G M Clore ◽  
E M Chance
Keyword(s):  
Magnetic Susceptibility ◽  
Low Temperature ◽  
Cytochrome Oxidase ◽  
Near Infrared ◽  
Optical Wavelength ◽  
Wavelength Scanning ◽  
Membrane Bound ◽  
Low Temperature Kinetics ◽  
Kinetics Of

The kinetics of the reaction of fully reduced membrane-bound cytochrome oxidase with O2 obtained in the Soret, alpha and near-i.r. regions were analysed, and the contributions of the three intermediates of the reaction [Clore & Chance (1978) Biochem. J. 173, 799–810] to seven wavelength pairs (430–463, 444–463, 590–630, 608–630, 740–940, 790–940 and 830–940 nm) were determined. The nature of the intermediates is discussed on the basis of the data in the present paper together with data in the literature from optical wavelength scanning, e.p.r., i.r. and magnetic-susceptibility studies.

scholarly journals Spectroscopic forms of carbonmonoxi-cytochrome oxidase

1979 ◽  
Vol 183 (2) ◽  
pp. 375-379 ◽  
Author(s):  
K de Fonseka ◽  
B Chance
Keyword(s):  
Low Temperature ◽  
Cytochrome Oxidase ◽  
Systematic Study ◽  
Residual Effect ◽  
Difference Spectra ◽  
Temperature Recording ◽  
Devitrification Process ◽  
Kinetics Of

A systematic study of the errors of low-temperature recording of kinetics of the cytochrome oxidase-CO reaction had identified the classic devitrification process of Keilin & Hartree [(1950) Nature (London)165, 504-505]. The methodology described here minimizes this effect, and the computation methods afford appropriate ways of detecting a residual effect. Thus it has been possible to identify that absorption difference spectra and kinetics of the reaction of fully reduced or half-reduced cytochrome oxidase with CO indicate only one spectroscopic form of the respective carbonmonoxi-cytochrome oxidase.

scholarly journals Low temperature kinetics of H+ changes of bacterial rhodopsin

1975 ◽  
Vol 15 (9) ◽  
pp. 913-917 ◽  
Author(s):  
B. Chance ◽  
M. Porte ◽  
B. Hess ◽  
D. Oesterhelt
Keyword(s):  
Low Temperature ◽  
Low Temperature Kinetics ◽  
Kinetics Of

Ultra‐low temperature kinetics of neutral–neutral reactions: The reaction CN+O2 down to 26 K

1992 ◽  
Vol 97 (11) ◽  
pp. 8798-8800 ◽  
Author(s):  
I. R. Sims ◽  
J. L. Queffelec ◽  
A. Defrance ◽  
C. Rebrion‐Rowe ◽  
D. Travers ◽  
...  
Keyword(s):  
Low Temperature ◽  
Low Temperature Kinetics ◽  
Kinetics Of

scholarly journals Low-temperature kinetics of the reaction of oxygen and solubilized cytochrome oxidase

1978 ◽  
Vol 171 (3) ◽  
pp. 787-798 ◽  
Author(s):  
B Chance ◽  
C Saronio ◽  
J S Leigh ◽  
W J Ingledew ◽  
T E King
Keyword(s):  
Cytochrome Oxidase ◽  
Mixed Valence ◽  
Similar Species ◽  
Absorption Bands ◽  
Compound C ◽  
Valence States ◽  
Membrane Bound ◽  
Peroxy Compounds ◽  
Band Characteristic ◽  
Kinetics Of

The reaction of solubilized cytochrome oxidase in the fully reduced state with O2 at low temperatures reveals components with characteristics similar to those observed with the membrane-bound oxidase, namely compounds A and B, which are proposed to be ‘oxy’ and ‘peroxy’ compounds respectively. Similar species are identified in both solubilized and membrane-bound oxidases; the reaction velocity constant for the reation with O2 and the dissociation constant are decreased 2-3-fold in the solubilied preparation as compared with the membrane-bound species, owing to decreased reactivity towards O2 in the former. The oxidase prepared in the mixed-valence state shows the distinctive absorption band characteristic of compound C, identified in the membrane-bound oxidase. The assignment of the alpha, beta, gamma and near-i.r. absorption bands to possible valence states of these compounds is made.

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