Effects of Amino Acids Protonation on Double-Layer Parameters of the Electrode/Chlorates(VII) Interface, as well as Kinetics and Mechanism of Bi(III) Ion Electroreduction in the Aspect of the “Cap–Pair” Effect

Author(s):  
Agnieszka Nosal-Wiercińska ◽  
Mariusz Grochowski ◽  
Małgorzata Wiśniewska
2000 ◽  
Vol 78 (8) ◽  
pp. 1052-1059 ◽  
Author(s):  
C Aliaga ◽  
E A Lissi

Stable free radicals derived from 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS·+) have been extensively employed to monitor the antioxidant capacity of biological fluids and beverages. Besides reacting with typical antioxidants (such as phenols or thiols) these radicals react with a variety of hydrogen or electron donors. The present work reports on the kinetics and mechanism of these radical reactions with several amino acids. Reaction rates notably increase when the pH of the media increases and, when measured under similar conditions, follows the ordercysteine > > tryptophan > tyrosine > histidine > cystineThe kinetics of the process is interpreted in terms of a mechanism comprising an initial pH dependent reversible step, followed by secondary reactions of the substrate derived radical with itself or with another ABTS·+; this simple three-step mechanism leads to very complex kinetic expressions. The specific rate constants of several of the elementary steps were determined by working under a wide range of substrate, radical, and ABTS concentrations. The values obtained for the initial interaction between the ABTS derived radical and the substrate range from 0.5 M–1 s–1 to 1.9 × 106 M–1 s–1 for histidine and cysteine, respectively.Key words: ABTS radical cation, 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid), amino acids, kinetics.


2018 ◽  
Vol 47 (40) ◽  
pp. 14174-14178
Author(s):  
Qi-ming Qiu ◽  
Leilei Gu ◽  
Hongwei Ma ◽  
Li Yan ◽  
Minghua Liu ◽  
...  

Double layer Zn–UDP coordination polymers with potentially open sites can be used for heterogeneous fluorescent sensors of amino acids.


2014 ◽  
Vol 145 (11) ◽  
pp. 1727-1735 ◽  
Author(s):  
Sumon Ray ◽  
Debabrata Nandi ◽  
Animesh Chattopadhyay ◽  
Roshni Sarkar ◽  
Parnajyoti Karmakar ◽  
...  

2004 ◽  
Vol 116 (2) ◽  
pp. 101-106 ◽  
Author(s):  
Raghvendra Shukla ◽  
Pradeep K. Sharma ◽  
Kalyan K. Banerji

Author(s):  
M. Shanmugan Ramachandram ◽  
T. Subburamiyer Vivekanandam ◽  
R. Patrick Malim Mani Raj

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