Self-Association ofm-Cresol in Aqueous Organic Solvents:  Relation to Enzymatic Polymerization Reaction

2002 ◽  
Vol 106 (6) ◽  
pp. 1421-1429 ◽  
Author(s):  
Takahisa Oguchi ◽  
Akihiro Wakisaka ◽  
Shin-ichiro Tawaki ◽  
Hiroyuki Tonami ◽  
Hiroshi Uyama ◽  
...  
Keyword(s):  
Organic Solvents ◽  
Enzymatic Polymerization ◽  
Polymerization Reaction ◽  
Self Association

Self-association of acetic acid in some organic solvents

1988 ◽  
Vol 92 (23) ◽  
pp. 6768-6772 ◽  
Author(s):  
Yukio Fujii ◽  
Hiromichi Yamada ◽  
Masateru Mizuta
Keyword(s):  
Acetic Acid ◽  
Organic Solvents ◽  
Self Association

Enzymatic Synthesis of Polyaniline/Graphite Oxide Nanocomposites

2012 ◽  
Vol 1448 ◽  
Author(s):  
C. Guerrero-Bermea ◽  
S. Sepulveda-Guzman ◽  
R. Cruz-Silva
Keyword(s):  
Graphite Oxide ◽  
Enzymatic Synthesis ◽  
Colloidal Stability ◽  
Aqueous Dispersion ◽  
Enzymatic Polymerization ◽  
Polymerization Reaction ◽  
As Doping ◽  
Fourier Transformed Infrared Spectroscopy ◽  
Vis Spectroscopy ◽  
Horseradish Peroxide

ABSTRACTIn this work, we prepared graphite oxide (GO)/polyaniline nanocomposites by enzymatic polymerization of aniline in an aqueous dispersion of graphite oxide. Two GO dispersions with sheets having an average lateral size of 12.50 μm and 247 nm were used. The enzymatic polymerization was carried out in aqueous acidic medium using toluenesulfonic acid (TSA) as doping agent, horseradish peroxide (HRP) as catalyst, and hydrogen peroxide as oxidizer. The polymerization reaction was studied using 1.0, 2.5 and 5 wt % of GO and nGO dispersions. No changes were observed in the catalytic activity of the peroxidase during the enzymatic synthesis due to the additionof GO sheets. Scanning electron microscopy images show that PANI colloids were attached on GO sheets. The PANI-GO colloids were characterized by ultraviolet–visible spectroscopy and Fourier transformed infrared spectroscopy, whereas their colloidal stability was evaluated at different pHs. The UV-vis spectroscopy study revealed that GO affects the electronic conjugation of PANI modifying its absorption spectrum.

scholarly journals Formation of Polyaniline and Polypyrrole Nanocomposites with Embedded Glucose Oxidase and Gold Nanoparticles

Polymers ◽  
2019 ◽  
Vol 11 (2) ◽  
pp. 377 ◽  
Author(s):  
Natalija German ◽  
Almira Ramanaviciene ◽  
Arunas Ramanavicius
Keyword(s):  
Gold Nanoparticles ◽  
Glucose Oxidase ◽  
Colloidal Gold ◽  
Sodium Acetate ◽  
Formation Rate ◽  
Bulk Composition ◽  
Enzymatic Polymerization ◽  
Polymerization Reaction ◽  
Sodium Acetate Buffer ◽  
Colloidal Gold Nanoparticles

Several types of polyaniline (PANI) and polypyrrole (Ppy) nanocomposites with embedded glucose oxidase (GOx) and gold nanoparticles (AuNPs) were formed by enzymatic polymerization of corresponding monomers (aniline and pyrrole) in the presence of 6 and 13 nm diameter colloidal gold nanoparticles (AuNPs(6nm) or AuNPs(13nm), respectively) or chloroaurate ions (AuCl4−). Glucose oxidase in the presence of glucose generated H2O2, which acted as initiator of polymerization reaction. The influence of polymerization bulk composition and pH on the formation of PANI- and Ppy-based nanocomposites was investigated spectrophotometrically. The highest formation rate of PANI- and Ppy-based nanocomposites with embedded glucose oxidase and gold nanoparticles (PANI/AuNPs-GOx and Ppy/AuNPs-GOx, respectively) was observed in the solution of sodium acetate buffer, pH 6.0. It was determined that the presence of AuNPs or AuCl4− ions facilitate enzymatic polymerization of aniline and pyrrole.

ChemInform Abstract: Self-Association of Acetic Acid in Some Organic Solvents

ChemInform ◽  
1989 ◽  
Vol 20 (10) ◽  
Author(s):  
Y. FUJII ◽  
H. YAMADA ◽  
M. MIZUTA
Keyword(s):  
Acetic Acid ◽  
Organic Solvents ◽  
Self Association

Aggregated, Conformationally Changed Fibrinogen Exposes the Stimulating Sites for t-PA-Catalysed Plasminogen Activation

1996 ◽  
Vol 75 (02) ◽  
pp. 326-331 ◽  
Author(s):  
Unni Haddeland ◽  
Knut Sletten ◽  
Anne Bennick ◽  
Willem Nieuwenhuizen ◽  
Frank Brosstad
Keyword(s):  
Conformational Changes ◽  
Gel Permeation Chromatography ◽  
Tissue Type ◽  
Plasminogen Activation ◽  
Chromogenic Substrate ◽  
Type Plasminogen Activator ◽  
Gel Permeation ◽  
Self Association ◽  
Fibrin Monomers ◽  
Stimulation Of

SummaryThe present paper shows that conformationally changed fibrinogen can expose the sites Aα-(148-160) and γ-(312-324) involved in stimulation of the tissue-type plasminogen activator (t-PA)-catalysed plasminogen activation. The exposure of the stimulating sites was determined by ELISA using mABs directed to these sites, and was shown to coincide with stimulation of t-PA-catalysed plasminogen activation as assessed in an assay using a chromogenic substrate for plasmin. Gel permeation chromatography of fibrinogen conformationally changed by heat (46.5° C for 25 min) demonstrated the presence of both aggregated and monomeric fibrinogen. The aggregated fibrinogen, but not the monomeric fibrinogen, had exposed the epitopes Aα-(148-160) and γ-(312-324) involved in t-PA-stimulation. Fibrinogen subjected to heat in the presence of 3 mM of the tetrapeptide GPRP neither aggregates nor exposes the rate-enhancing sites. Thus, aggregation and exposure of t-PA-stimulating sites in fibrinogen seem to be related phenomena, and it is tempting to believe that the exposure of stimulating sites is a consequence of the conformational changes that occur during aggregation, or self-association. Fibrin monomers kept in a monomeric state by a final GPRP concentration of 3 mM do not expose the epitopes Aα-(148-160) and γ-(312-324) involved in t-PA-stimulation, whereas dilution of GPRP to a concentration that is no longer anti-polymerizing, results in exposure of these sites. Consequently, the exposure of t-PA-stimulating sites in fibrin as well is due to the conformational changes that occur during selfassociation.

UNTERSUCHUNGEN ÜBER DIE EXTRAKTION DES ROTEN KOBER-FARBSTOFFS DURCH ORGANISCHE LÖSUNGSMITTEL ZUR ÖSTROGENBESTIMMUNG IM HARN

1960 ◽  
Vol XXXV (I) ◽  
pp. 34-48 ◽  
Author(s):  
Gerd Ittrich
Keyword(s):  
Menstrual Cycle ◽  
Organic Solvents ◽  
Urine Sample ◽  
Phenol Derivatives ◽  
Organische Lösungsmittel ◽  
Colour Complex

ABSTRACT A series of organic solvents and phenol derivatives have been examined for the extraction of the pink Kober-colour complex. Optimal results could be achieved for fluorimetry by a solution of 2 % (w/v) p-nitrophenol and 1 % (v/v) ethanol in acetylenetetrabromide, when the green mercury line (546 mμ was used as primary light. The sensitivity, stability and specificity have been improved, compared with the previously described reaction. By changing the sequence of purification steps and by reducing the volume of the urine sample (5 ml) the method for the determination of total oestrogens has been simplified. Approximately 10 determinations can be done within 3–4 hours by one person. Recovery experiments and comparative determinations with a previously described method have been carried out. The excretion of total oestrogens in a complete menstrual cycle is determined with the described method.

Self-association of insulin. Its pH dependence and effect of plasma

Diabetes ◽  
1987 ◽  
Vol 36 (3) ◽  
pp. 261-264 ◽  
Author(s):  
E. Helmerhorst ◽  
G. B. Stokes
Keyword(s):  
Ph Dependence ◽  
Self Association
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