Removal of phenols from aqueous solutions in the presence of horseradish peroxidase and cyclodextrien derivatives

1996 ◽  
Vol 25 (1-3) ◽  
pp. 225-228 ◽  
Author(s):  
F. Trotta ◽  
R.P. Ferrari ◽  
E. Laurenti ◽  
G. Moraglio ◽  
A. Trossi
Keyword(s):  
Horseradish Peroxidase ◽  
Aqueous Solutions

Removal of Linear and Branched Alkylphenols from Aqueous Solutions with Horseradish Peroxidase

2008 ◽  
Vol 72 (5) ◽  
pp. 1368-1371 ◽  
Author(s):  
Naoya IKEDA ◽  
Kazunori YAMADA ◽  
Takashi SHIBUYA ◽  
Ayumi KASHIWADA ◽  
Kiyomi MATSUDA ◽  
...  
Keyword(s):  
Horseradish Peroxidase ◽  
Aqueous Solutions

scholarly journals Studies on horseradish peroxidase in dimethyl sulphoxide/water mixtures. The activation of hydrogen peroxide and the binding of fluoride

1979 ◽  
Vol 179 (2) ◽  
pp. 273-280 ◽  
Author(s):  
P A Adams ◽  
D A Baldwin ◽  
G S Collier ◽  
J M Pratt
Keyword(s):  
Hydrogen Peroxide ◽  
Enzyme Activity ◽  
Horseradish Peroxidase ◽  
Aqueous Solutions ◽  
Similar Pattern ◽  
Solvent Mixture ◽  
Dimethyl Sulphoxide ◽  
Stock Solutions ◽  
Activation Of Hydrogen Peroxide

We studied the variation in spectra and in reactivity towards H2O2 of solutions of horseradish peroxidase in dimethyl sulphoxide/water mixtures, obtained by diluting stock solutions of the enzyme in either water or dimethyl sulphoxide, and assayed the enzyme activity and studied the binding of F- by the peroxidase in 65% (v/v) dimethyl sulphoxide. A broadly similar pattern of changes is observed whether one starts from water or from dimethyl sulphoxide; the changes are essentially reversible, though hysteresis is observed. When the dimethyl sulphoxide content of the solvent mixture is increased, the peroxidase retains its ability to activate H2O2 up to 74% (v/v) dimethyl sulphoxide. The peroxidase in 65% (v/v) dimethyl sulphoxide binds F- together with a proton (or the equivalent loss of HO-), as already established for aqueous solutions. We point out that the occurrence in such solutions of both the ability to activate H2O2 and the inability to bind F- without taking up H+ or losing HO- supports the proposed mechanism for activating H202, whereby the protein binds the substrate in the form of the much more reactive HO2-.

scholarly journals Oxidation of 2-nitropropane by horseradish peroxidase. Involvement of hydrogen peroxide and of superoxide in the reaction mechanism

1978 ◽  
Vol 175 (2) ◽  
pp. 601-606 ◽  
Author(s):  
Johan De Rycker ◽  
Barry Halliwell
Keyword(s):  
Hydrogen Peroxide ◽  
Superoxide Dismutase ◽  
Reaction Mechanism ◽  
Horseradish Peroxidase ◽  
Aqueous Solutions ◽  
Oxidation Reaction ◽  
Superoxide Ion ◽  
Radical Species ◽  
Ph Optimum ◽  
Nitro Aromatics

Incubation of aqueous solutions of 2-nitropropane in air causes a slow oxidation reaction that generates H2O2. Purified horseradish peroxidase catalyses the oxidation of such preincubated 2-nitropropane solutions according to the equation: [Formula: see text] The pH optimum is 4.5 and Km for 2-nitropropane is 16mm. Other nitroalkanes or nitro-aromatics tested are not oxidized at significant rates by peroxidase. H2O2 or 2,4-dichlorophenol increases the rate of 2-nitropropane oxidation by peroxidase. Catalase inhibits the reaction completely. Superoxide dismutase or mannitol, a scavenger of the hydroxyl radical, OH., each inhibits partially. Aniline and guaiacol are also powerful inhibitors of 2-nitropropane oxidation. It is suggested that peroxidase uses the traces of H2O2 generated during preincubation of 2-nitropropane to catalyse oxidation of this substrate into a radical species that can reduce O2 to the superoxide ion, O2−..O2−., or OH. derived from it, then appears to react with more nitropropane, generating further radicals and H2O2 to continue the oxidation. Inhibition by aniline and guaiacol seems to be due to a competition for H2O2.

Ultrathin frozen sections of yeast without aldehyde prefixation

1978 ◽  
Vol 36 (2) ◽  
pp. 58-59
Author(s):  
K. J. Böhm ◽  
a. E. Unger
Keyword(s):  
Aqueous Solutions ◽  
Biological Material ◽  
Yeast Cells ◽  
Frozen Sections ◽  
Good Preservation ◽  
Ultrathin Frozen Sections

During the last years it was shown that also by means of cryo-ultra-microtomy a good preservation of substructural details of biological material was possible. However the specimen generally was prefixed in these cases with aldehydes.Preparing ultrathin frozen sections of chemically non-prefixed material commonly was linked up to considerable technical and manual expense and the results were not always satisfying. Furthermore, it seems to be impossible to carry out cytochemical investigations by means of treating sections of unfixed biological material with aqueous solutions.We therefore tried to overcome these difficulties by preparing yeast cells (S. cerevisiae) in the following manner:

Effects of Vincristine on Endothelial Microtubules in the Spinal Cord

1976 ◽  
Vol 34 ◽  
pp. 58-59
Author(s):  
John L. Beggs ◽  
John D. Waggener ◽  
Wanda Miller
Keyword(s):  
Spinal Cord ◽  
Biological Activity ◽  
Horseradish Peroxidase ◽  
Transport Mechanism ◽  
Vasogenic Edema ◽  
Vesicular Transport ◽  
Close Proximity

Microtubules (MT) are versatile organelles participating in a wide variety of biological activity. MT involvement in the movement and transport of cytoplasmic components has been well documented. In the course of our study on trauma-induced vasogenic edema in the spinal cord we have concluded that endothelial vesicles contribute to the edema process. Using horseradish peroxidase as a vascular tracer, labeled endothelial vesicles were present in all situations expected if a vesicular transport mechanism was in operation. Frequently,labeled vesicles coalesced to form channels that appeared to traverse the endothelium. The presence of MT in close proximity to labeled vesicles sugg ested that MT may play a role in vesicular activity.

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