Kinetics and mechanism of decomposition of N-chloro-α-amino acids

1990 ◽  
pp. 1233-1238 ◽  
Author(s):  
Riad Awad ◽  
Anwar Hussain ◽  
Peter A. Crooks
Keyword(s):  
Amino Acids ◽  
Kinetics And Mechanism ◽  
Mechanism Of Decomposition

Reactions of the radical cation derived from 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS·+) with amino acids. Kinetics and mechanism

2000 ◽  
Vol 78 (8) ◽  
pp. 1052-1059 ◽  
Author(s):  
C Aliaga ◽  
E A Lissi
Keyword(s):  
Amino Acids ◽  
Radical Cation ◽  
Sulfonic Acid ◽  
Biological Fluids ◽  
Reaction Rates ◽  
Kinetics And Mechanism ◽  
Specific Rate ◽  
Wide Range ◽  
Initial Ph ◽  
Secondary Reactions

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.

Kinetics and mechanism of reactions of some essential amino acids with cis-diaqua(1,3-diaminopropane)-platinum(II) ion: a potent anticancer agent

2014 ◽  
Vol 145 (11) ◽  
pp. 1727-1735 ◽  
Author(s):  
Sumon Ray ◽  
Debabrata Nandi ◽  
Animesh Chattopadhyay ◽  
Roshni Sarkar ◽  
Parnajyoti Karmakar ◽  
...  
Keyword(s):  
Amino Acids ◽  
Anticancer Agent ◽  
Essential Amino Acids ◽  
Kinetics And Mechanism
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