The acidity and stability constants of M-L (M: M2+;L: Met, L-methionine) complexes, determined by potentiometric pH titrations, were used to make a comparative investigation. The stability constants of the 1:1 complex...The acidity and stability constants of M-L (M: M2+;L: Met, L-methionine) complexes, determined by potentiometric pH titrations, were used to make a comparative investigation. The stability constants of the 1:1 complexes formed between M2+ and L–, were determined by potentiometric pH titration in aqueous solution (I = 0.1 M, NaNO3, 25°C). The order of the stability constants was reported. It is shown that regarding to M ion – binding properties, vital differences on complex bilding were considered. It is demonstrated that in M-L complexes, M ion is coordinated to the carboxyl group, is also able to bild macrochelate over amine group. The aforementioned results demonstrate that for M (Met) complex, the stability constants are also largely determined by the affinity of Cu ion for amino group. It is indicated that this additional interaction with amino groups can influence the character of some amino acid complexes in biological systems.展开更多
A comparative research has been developed for acidity and stability constants of M(TTA)1 and M(Asp)2 complexes which have been determined by potentiometric pH titration. Depending on metal ion–binding properties, vit...A comparative research has been developed for acidity and stability constants of M(TTA)1 and M(Asp)2 complexes which have been determined by potentiometric pH titration. Depending on metal ion–binding properties, vital differences in building complex were observed. The present study shows that in M(TTA) complexes, metal ions are coordinated to the carboxyl groups, but in M(Asp) some metal ions are able to build macrochelate over amine group. Hence, the following intermolecular and as a result independent concentration equilibrium between an open–isomer M(Asp)op and a closed–isomer M(Asp)cl, has to be considered cl op. The amounts are reported. The results mentioned above demonstrate that for some M(Asp) complexes the stability constants is also largely determined by the affinity of metal ions for amine group. This leads to a kind of selectivity of metal ions and transfer them via building complexes with the aspartate. The result of this effect is a higher dosage-absorption of minerals in body. Based on the sort of metal ions, the drug-therapy can be different. For heavy metal ions this building complex helps the absorption and filtration of the blood plasma, and consequently the excursion of heavy metal ions takes place. This is an important method in microdialysis. Other metal ions such as the complexes can be considered as mineral carriers. These complexes in certain conditions (PH–range) can release the minerals in body.展开更多
文摘The acidity and stability constants of M-L (M: M2+;L: Met, L-methionine) complexes, determined by potentiometric pH titrations, were used to make a comparative investigation. The stability constants of the 1:1 complexes formed between M2+ and L–, were determined by potentiometric pH titration in aqueous solution (I = 0.1 M, NaNO3, 25°C). The order of the stability constants was reported. It is shown that regarding to M ion – binding properties, vital differences on complex bilding were considered. It is demonstrated that in M-L complexes, M ion is coordinated to the carboxyl group, is also able to bild macrochelate over amine group. The aforementioned results demonstrate that for M (Met) complex, the stability constants are also largely determined by the affinity of Cu ion for amino group. It is indicated that this additional interaction with amino groups can influence the character of some amino acid complexes in biological systems.
文摘A comparative research has been developed for acidity and stability constants of M(TTA)1 and M(Asp)2 complexes which have been determined by potentiometric pH titration. Depending on metal ion–binding properties, vital differences in building complex were observed. The present study shows that in M(TTA) complexes, metal ions are coordinated to the carboxyl groups, but in M(Asp) some metal ions are able to build macrochelate over amine group. Hence, the following intermolecular and as a result independent concentration equilibrium between an open–isomer M(Asp)op and a closed–isomer M(Asp)cl, has to be considered cl op. The amounts are reported. The results mentioned above demonstrate that for some M(Asp) complexes the stability constants is also largely determined by the affinity of metal ions for amine group. This leads to a kind of selectivity of metal ions and transfer them via building complexes with the aspartate. The result of this effect is a higher dosage-absorption of minerals in body. Based on the sort of metal ions, the drug-therapy can be different. For heavy metal ions this building complex helps the absorption and filtration of the blood plasma, and consequently the excursion of heavy metal ions takes place. This is an important method in microdialysis. Other metal ions such as the complexes can be considered as mineral carriers. These complexes in certain conditions (PH–range) can release the minerals in body.
