Effects of axial ligation on molecular oxygen binding by donor atoms built in saturated macrocycles. Equilibrium and kinetic study with cobalt(II) complexes of macrocyclic pentaamines and oxatetraamine

1980 ◽  
Vol 19 (7) ◽  
pp. 1871-1875 ◽  
Author(s):  
Mutsuo Kodama ◽  
Eiichi Kimura
Keyword(s):  
Kinetic Study ◽  
Molecular Oxygen ◽  
Oxygen Binding ◽  
Axial Ligation

Kinetic study of the reduction of molecular oxygen by cuprous chloride and cuprous acetate in pyridine

1983 ◽  
Vol 87 (23) ◽  
pp. 4681-4686 ◽  
Author(s):  
Frederick R. Hopf ◽  
Milorad M. Rogic ◽  
James F. Wolf
Keyword(s):  
Kinetic Study ◽  
Molecular Oxygen ◽  
Cuprous Chloride

scholarly journals A Kinetic Study on the Oxidation of Ferrous Ion with Dissolved Molecular Oxygen

1979 ◽  
Vol 47 (7) ◽  
pp. 409-414 ◽  
Author(s):  
Masao IWAI ◽  
Hiroshi MAJIMA ◽  
Toshio IZAKI
Keyword(s):  
Kinetic Study ◽  
Molecular Oxygen ◽  
Ferrous Ion

scholarly journals The haem b558 component of the cytochrome bd quinol oxidase complex from Escherichia coli has histidine-methionine axial ligation

1995 ◽  
Vol 308 (2) ◽  
pp. 641-644 ◽  
Author(s):  
F Spinner ◽  
M R Cheesman ◽  
A J Thomson ◽  
T Kaysser ◽  
R B Gennis ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Near Infrared ◽  
Magnetic Circular Dichroism ◽  
Site Directed Mutagenesis ◽  
Oxygen Binding ◽  
Axial Ligation ◽  
Cytochrome Bd ◽  
Axial Ligands ◽  
Aeration Conditions ◽  
Electron Reduction

The cytochrome bd ubiquinol oxidase from Escherichia coli is induced when the bacteria are cultured under microaerophilic or low-aeration conditions. This membrane-bound respiratory oxidase catalyses the two-electron oxidation of ubiquinol and the four-electron reduction of dioxygen to water. The oxidase contains three haem prosthetic groups: haem b558, haem b595 and haem d. Haem d is the oxygen binding site, and it is likely that haem d and b595 form a bimetallic site in the enzyme. Haem b558 has been previously characterized spectroscopically as being low spin and has been shown to be located within subunit I (CydA) of this two-subunit enzyme. It is likely that haem b558 is associated with the quinol oxidation site, which has also been shown to be within subunit I. In a previous effort to locate the specific amino acids axially ligated to haem b558, all six histidines within subunit I were altered by site-directed mutagenesis. Only one, histidine-186, was identified as a likely ligand to haem b558. Hence it was suggested that haem b558 could not have bis(histidine) ligation. In the current work, a combination of low-temperature near-infrared magnetic circular dichroism (NIR-MCD) and EPR spectroscopies have been employed to identify the nature of the haem b558 axial ligands. The NIR-MCD spectrum at cryogenic temperatures is dominated by the low-spin haem b558 component of the complex, and the low-energy band near 1800 nm is strong evidence for histidine-methionine ligation. It is concluded that haem b558 is ligated to histidine-186 plus one of the methionines located within subunit I of the oxidase.

The formation of O2(a1Δg) in homogeneous and heterogeneous atom recombination

1986 ◽  
Vol 64 (12) ◽  
pp. 1614-1620 ◽  
Author(s):  
A. A. Ali ◽  
E. A. Ogryzlo ◽  
Y. Q. Shen ◽  
P. T. Wassell
Keyword(s):  
Kinetic Study ◽  
Gas Phase ◽  
Molecular Oxygen ◽  
Rate Constant ◽  
Room Temperature ◽  
High Efficiency ◽  
Flow System ◽  
Order Reaction ◽  
Third Order ◽  
First Order

The recombination of oxygen atoms has been studied in a discharge flow system at room temperature. The yield of O2(a1Δg) in the recombination on Pyrex has been found to be 0.08 (±0.02). In the gas phase, O2(a) was found to be formed in a process that is second order in [O] and first order in [N2]. The rate constant for this third-order reaction was found to be 3.4 (±0.4) × 10−34 cm6∙molecule−2∙s−1, representing a yield of 0.07 (±0.02). In the presence of molecular oxygen, the rate of production of O2(a) was found to increase. A kinetic study of this effect led to the conclusion that collisions of molecular oxygen with an unidentified precursor can produce O2(a) with high efficiency.

Polymerization of methyl methacrylate in the presence of molecular oxygen — a kinetic study

Polymer ◽  
1981 ◽  
Vol 22 (12) ◽  
pp. 1692-1698 ◽  
Author(s):  
G.Gangi Reddy ◽  
T. Nagabhushanam ◽  
K. Venkata Rao ◽  
M. Santappa
Keyword(s):  
Methyl Methacrylate ◽  
Kinetic Study ◽  
Molecular Oxygen
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