Kinetic studies on the decomposition of the 4-diethylaminoantipyrine cation radical in aqueous acetonitrile solutions.

1979 ◽  
Vol 27 (8) ◽  
pp. 1919-1922
Author(s):  
HIROTERU SAYO
Keyword(s):  
Cation Radical ◽  
Kinetic Studies ◽  
Aqueous Acetonitrile ◽  
Acetonitrile Solutions

Anodic behaviour of limonene in low aqueous acetonitrile solutions of Cl−

1988 ◽  
Vol 66 (7) ◽  
pp. 1757-1762 ◽  
Author(s):  
J. A. Caram ◽  
M. E. Martins ◽  
E. G. Gros ◽  
C. M. Marschoff
Keyword(s):  
Water Content ◽  
Aqueous Acetonitrile ◽  
Pt Electrodes ◽  
Acetonitrile Solutions ◽  
Anodic Behaviour ◽  
Derivatives Of ◽  
Reaction Routes

The anodic behaviour of limonene on Pt electrodes was studied in LiCl solutions in acetonitrile with low water content. It was found that cis-6-acetamido-p-menth-1,8-diene is formed with acceptable yields. This compound is of interest as a potential intermediate for obtaining oxidation derivatives of limonene. Other products, among them the new compound 8-acetamido-2,4,8-trimethyl-4-chloromethyl-3-aza-bicyclo[3.3.1]non-2-ene, were identified. Reaction routes are proposed.

scholarly journals NN-dimethyl-1,4-phenylenediamine as an alternative reductant for peptidylglycine α-amidating mono-oxygenase catalysis

1994 ◽  
Vol 300 (1) ◽  
pp. 31-36 ◽  
Author(s):  
C Li ◽  
C D Oldham ◽  
S W May
Keyword(s):  
Cation Radical ◽  
Kinetic Studies ◽  
Peptide Hormone ◽  
Steady State Kinetic ◽  
Rate Of Increase ◽  
Ping Pong ◽  
Assay Methods ◽  
Menten Kinetic ◽  
Continuous Assay ◽  
State Kinetic

C-terminal alpha-amidation is a structural feature essential to the biological activity of many peptide hormones. Peptidylglycine alpha-amidating mono-oxygenase (PAM; EC 1.14.17.3) catalyses conversion of glycine-extended peptide hormone precursors into their corresponding alpha-hydroxyglycine derivatives. This reaction is the first step in the C-terminal amidation process. We report here that in the presence of molecular O2, copper and PAM substrate, NN-dimethyl-1,4-phenylenediamine (DMPD) serves as the requisite electron donor for the mono-oxygenase, being oxidized in the process to a stable and highly chromophoric cation radical. By monitoring the rate of increase in absorbance at 515 nm, PAM activity can be easily followed. This provides a spectrophotometric assay for PAM, which represents the first continuous assay reported for this enzyme. DMPD-supported PAM-catalysed mono-oxygenation exhibits normal Michaelis-Menten kinetic behaviour. Steady-state kinetic studies established that both the ascorbate-supported and DMPD-supported PAM reactions exhibit apparent ‘Ping Pong’ kinetics. In addition, both electron donors give rise to similar pH profiles and identical inhibition patterns towards known competitive inhibitors of PAM. The stoichiometry between formation of the DMPD cation radical and the alpha-hydroxyglycine PAM product was determined to be 2:1, the value expected for a monooxygenase-catalysed reaction. The optimum pH for the DMPD-supported continuous PAM assay was found to be about 5.5. The major advantage of this assay over all previously reported methods is that it is continuous; thus accurate initial rates are easily obtained. Moreover, unlike previous assay methods, 125I-labelled or chromophorically modified substrates are not required. Kinetic parameters for a broad range of PAM substrates and inhibitors have been successfully obtained using this assay.

Poly (SNS) Quantitative Electrosynthesis and Electrodissolution

1993 ◽  
Vol 328 ◽  
Author(s):  
T. F. Otero ◽  
E. Brillas ◽  
J. Carrasco ◽  
A. Figueras
Keyword(s):  
Conducting Polymers ◽  
Thick Films ◽  
Industrial Applications ◽  
Cathodic Reduction ◽  
Acetonitrile Solution ◽  
Aqueous Acetonitrile ◽  
Acetonitrile Solutions

ABSTRACTThe electrogeneration and electrodissolution of poly (SNS) have been improved by using aqueous acetonitrile solutions having a 1% (ν/ν) of water constant. Compact, adherent and thick films (until 0.4 Mg cm-2) were galvanostatically electrogenerated. The electrodeposited (oxidized) polymer is insoluble in 0.1 M L?CIO4 aqueous acetonitrile solution and solubilizes by cathodic reduction. Both, electrogeneration and electrodissolution, are faradaic processes. Those facts mimic electrodeposition and electroerosion of metals and their concomitant industrial applications. New technological possibilities using polymers in electrophotography, electroreprography, electropolishing, electro-erosion and electromachining are open through polymeric electrodissolution altogether to a new processible way, through the obtained solution, for the conducting polymers.

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