Effects of gamma-ray-induced free radicals on the metal content and amino acid composition of human metallothionein-1.
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Date
2011-06
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Abstract
Metallothioneins (MTs), a low-mass class of metalloproteins, are characterized by a high thiolate sulphur and metal
content. MTs are involved in metal homeostasis and heavy metal detoxification, and are efficient scavengers of free
radicals. This article describes zinc release from human MT-1 and modification of its amino acid composition when
subjected to free radicals generated during gamma ray radiolysis. The effect of gamma ray radiolysis of untreated and
metal-depleted human MT-1 was tested under multiple aerobic and anaerobic conditions at increasing irradiation
doses. Under all conditions, a rapid increase of serine in the early stages of irradiation was observed. Irradiation for
longer times led to cysteic acid formation, except under argon atmosphere. Several other amino acid concentrations
gradually decreased. Formation of limited amounts of hydroxyproline, hydroxylysine and ornithine as well as some
less common derivatives such as cystathionine occurred as side-effects.
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Keywords
Amino acid modification, gamma ray radiolysis, hydroxyl radical, metallothionein, zinc release
Citation
Goossens Lieven. Effects of gamma-ray-induced free radicals on the metal content and amino acid composition of human metallothionein-1. Journal of Biosciences. 2011 Jun; 36(2): 235-241.