HYDROLYSIS AND DEUTERATION OF GLYCYLGLYCINE CATALYZED BY DINUCLEAR [BMXDCu<sub> 2</sub>]<sup>4+ </sup> COMPLEX
Abstract:
<p align="justify"> Kinetic studies of hydrolysis and deuteration of glycylglycine by dinuclear [BMXDCu<sub> 2</sub>]<sup>4+</sup> complexes were following by NMR1H. Two parallel reactions were observed for the ternary system BMXD-Cu<sub> 2</sub>-Glycylglycine: peptide bond hydrolysis and NCH<sub>2</sub> deuteration reactions. The reaction rates show the first-order behavior to the concentration of the ternary [BMXDCu2Glycylglycine] complex. The specific rate constants for the hydrolysis reaction are: KLCu<sub>2</sub>HGG<sup>4+</sup> (L = BMXD and GG = glycylglycine) = 1,8 x 10<sup>-6</sup> s<sup>-1</sup>; KLCu<sub> 2</sub>GG<sup>3+</sup> = 2,3 x 10<sup>-6</sup> s<sup>-1</sup>; KLCu<sub>2</sub>H-1GG<sup>2+</sup>, KLCu<sub> 2</sub>(OH)H<sub>-1</sub>GG<sup>+</sup> and KLCu<sub> 2</sub>(OH)<sub> 2</sub>H<sub>-1</sub>GG = 0, and the specific deuteration rate constants for individual species are: KLCu<sub> 2</sub>HGG<sup>4+</sup> = 3,9 x 10<sup>-6</sup> s<sup>-1</sup>; KLCu<sub> 2</sub>GG<sup>3+</sup> = 4,3 x 10<sup>-6</sup> s<sup>-1</sup>; KLCu<sub>2</sub>H-1GG<sup>2+</sup>, KLCu<sub>2</sub>(OH)H<sub>-1</sub>GG<sup>+</sup> and KLCu<sub>2</sub>(OH)2H<sub>-1</sub>GG = 0. The results show that the most active species toward hydrolysis and deuteration reactions are the protonated and non-protonated species, the former being the most reactive species. Semi-empirical calculations for energy minimization showed that the binuclear [BMXDCu<sub> 2</sub>]<sup>4+</sup>) complexes adopt the boat-type conformation, in order to accommodate the dipeptide glycylglycine. </p>
<p align="justify"> Kinetic studies of hydrolysis and deuteration of glycylglycine by dinuclear [BMXDCu<sub> 2</sub>]<sup>4+</sup> complexes were following by NMR1H. Two parallel reactions were observed for the ternary system BMXD-Cu<sub> 2</sub>-Glycylglycine: peptide bond hydrolysis and NCH<sub>2</sub> deuteration reactions. The reaction rates show the first-order behavior to the concentration of the ternary [BMXDCu2Glycylglycine] complex. The specific rate constants for the hydrolysis reaction are: KLCu<sub>2</sub>HGG<sup>4+</sup> (L = BMXD and GG = glycylglycine) = 1,8 x 10<sup>-6</sup> s<sup>-1</sup>; KLCu<sub> 2</sub>GG<sup>3+</sup> = 2,3 x 10<sup>-6</sup> s<sup>-1</sup>; KLCu<sub>2</sub>H-1GG<sup>2+</sup>, KLCu<sub> 2</sub>(OH)H<sub>-1</sub>GG<sup>+</sup> and KLCu<sub> 2</sub>(OH)<sub> 2</sub>H<sub>-1</sub>GG = 0, and the specific deuteration rate constants for individual species are: KLCu<sub> 2</sub>HGG<sup>4+</sup> = 3,9 x 10<sup>-6</sup> s<sup>-1</sup>; KLCu<sub> 2</sub>GG<sup>3+</sup> = 4,3 x 10<sup>-6</sup> s<sup>-1</sup>; KLCu<sub>2</sub>H-1GG<sup>2+</sup>, KLCu<sub>2</sub>(OH)H<sub>-1</sub>GG<sup>+</sup> and KLCu<sub>2</sub>(OH)2H<sub>-1</sub>GG = 0. The results show that the most active species toward hydrolysis and deuteration reactions are the protonated and non-protonated species, the former being the most reactive species. Semi-empirical calculations for energy minimization showed that the binuclear [BMXDCu<sub> 2</sub>]<sup>4+</sup>) complexes adopt the boat-type conformation, in order to accommodate the dipeptide glycylglycine. </p>
DOI: 10.48141/SBJCHEM.v15.n15.2007.21_revistadec2007partial.pdf
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