engleski

The role of metallothioneins in detoxification and oxidative stress

Metallothineins (MTs) are low-molecular weight, metal-bindig proteins, rich in cysteine residues, present in virtually all living organisms. They are localized mainly in the cell cytoplasm, but can also be present in lysosomes, mitochondria and nuclei. MT molecule is a single polypeptide chain with more than one-third of amino acids being Cys residues, which can act as metal binding domains [1]. Therefore, the key role of MTs is maintaining the homeostasis of essential metals like Zn, but they also have high affinity for binding toxic metals like Cd, Hg and Pb. Due to their potent metal-binding and redox capabilities, important biological functions of MTs include heavy-metal detoxification, free radicals scavenging and protection of cells against the oxidative stress [1, 2]. Metal ions can induce MTs expression which can be used as a biomarker indicating environmental contamination with toxic metals [2]. MTs regulate levels of free radicals, shortly lived chemical particles containing one or more unpaired electrons generated by radiation and various biological processes. It was shown that MT can act as scavengers of superoxide and hydroxyl radicals or as Zn donor for enzymes participating in repairing processes and cell protection [3].

metallothionein, toxic metals, free radicals, oxidative stress

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