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Biomimetic Model of Coenzyme B12: Aquabis(ethane-1,2-diamine-κN,κN′)ethylcobalt(III) – Its Kinetic and Binding Studies with Imidazoles and Amino Acids and Interactions with CT DNA

✍ Scribed by Ponuganti Pallavi; Penumaka Nagababu; Sirasani Satyanarayana


Publisher
John Wiley and Sons
Year
2007
Tongue
German
Weight
231 KB
Volume
90
Category
Article
ISSN
0018-019X

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✦ Synopsis


Pseudo-first-order reaction kinetics and binding studies of trans-[Co(en) 2 (Et)H 2 O] complex with 1H-imidazole, substituted 1H-imidazoles, histidine, histamine, glycine and glycine ethyl ester were investigated by means of spectrophotometric techniques. Equilibrium constants were determined as a function of pH at 258. Binding and kinetic studies were correlated to basicity and steric hindrance. From the equilibrium data, it was found that the entering nucleophile is participating in the transition state, an I d mechanism is proposed. The effect of the incoming ligands on the complex was studied by molecular mechanics. The interaction of trans-[Co(en) 2 (Et)H 2 O] with CT DNA was studied spectrophotometrically.

Experimental. -General. tert-Butyl carbazate (¼ tert-butyl hydrazinecarboxylate), acetone, bromoethane, histidine, histamine, 1H-imidazole, 1-methyl-1H-imidazole, 2-methyl-1H-imidazole, 1,2-dimethyl-1H-imidazole, glycine, and glycine ethyl ester were purchased from Sigma-Aldrich Chemicals.

with the incoming nucleophile suggesting that the nucleophile is taking part in the transition state. Thus, an I d mechanism is proposed. The binding studies suggest that the complex [Co(en) 2 (Et)OH 2 ] binds with DNA.