Pro(anti)oxidant Properties of Amino Acids and Their Derivatives in The Presence of Fe<sup>2+</sup> and Cu<sup>2+</sup> Ions
Fluorescent probe, terephthalic acid, was used for rapid analysis of the ability of amino acids and their derivatives to accept and/or promote the formation of HO˙ radicals in the Cu2+-H2O2, Fe2+/EDTA-H2O2 systems. In the concentration range of 0.005-30 mM., according to the increase in IC50, amino acids are ranked as follows: Trp 2+); His ≤ Met 2+). In the presence of copper(II), Cys and its derivatives, Glu, α-Ala, His (S) intensify HO˙ formation, and act as antioxidants in molar ratio of S:Cu2+ > 2:1, only for His this ratio is ≥1:1. Cys is also a prooxidant in the system with Fe2+/EDTA.