Notice of RetractionStudy of Stabilities of L-Cysteine and L-Methionine with Divalent Metal Ions: A Comparison of Thermodynamic Data

Notice of Retraction

After careful and considered review of the content of this paper by a duly constituted expert committee, this paper has been found to be in violation of IEEE´s Publication Principles.

We hereby retract the content of this paper. Reasonable effort should be made to remove all past references to this paper.

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The acidity and stability constants of M-Met (M: M²⁺; Met¹: L-methionine) complexes, determined by potentiometric pH titrations, were used to make a comparative investigation with L-cysteine (Cys). It is shown that regarding to M ion - binding properties vital differences on complex bilding were considered. It is demonstrated, that in M-Met complexes, M ion is coordinated to the carboxyl group, M ion is also able to build macrochelate over amine group. The upmentioned results demonstrate that for M-Met complex the stability constants is also largely determined by the affinity of Cu²⁺ for amino group but in opposite to Met, some metal ions such as Co²⁺, Cu²⁺, and Zn²⁺ build with Cys² macrochelate over sulfur group. It is shown that this additional interaction with amino group and sulfur group can influence the character of some amino acid complexes in biological systems. The regarding ΔG^o values are calculated and reported. The interesting point of this work is the ΔG^o differences between M-Cys and M-Met complexes.