engleski

Real-time monitoring of “self-oxidation” of cysteine in presence of Cu2+ : Novel findings in the oxidation mechanism

A novel approach to investigation of a mechanism and rate of "self-oxidation" of cysteine in the presence of Cu2+ is presented. Continuous monitoring was performed using simple, low-cost and widely available commercial ion-selective electrode for Cu2+. Presented procedure provides a complete real-time picture of overall oxidation process and has revealed a sequentially organized process, with the domination of certain reactions in each stage. A plausible mechanism, in the light of the previously reported explanation, has been proposed to account for the experimental results together with an adequate scheme of the overall process. The dependence of both the pH (measurements were performed at pH 5, 7, 8) and the concentration of the initially present Cu2+ are presented and discussed. Additionally, information in to the process was collected by experiments performed in oxygen-free atmosphere and changes in the mechanism of oxidation, at weakly alkaline pH values, were observed. Information presented in this study can be utilized in advanced biochemical monitoring systems, when considering the importance of the position of cysteine and cysteine containing peptides in metabolic processes.

Metal complexes ; Amino acids ; Bioinorganic chemistry ; Sensors

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