Nishikimi M, Ozawa T
Biochem Int. 1987 Jan;14(1):111-7.
Among the seven chelating agents tested, ethylenediamine di(o-hydroxyphenylacetic acid) and diethylenetriamine pentaacetic acid were found to almost completely inhibit ascorbate oxidation catalyzed by iron ions. The inhibition with the former chelator is due to the prevention of the reduction of Fe3+ by ascorbate, while the inhibition with the latter is caused by the strong inhibition of both this reductive reaction and the oxidation of Fe2+ by O2. These chelators almost completely inhibit ascorbate oxidation catalyzed by copper ions as well. These results indicate that the blocking of redox cycling of metal ions is important to prevent the oxidation of ascorbate.
在所测试的七种螯合剂中，乙二胺二（邻羟基苯乙酸）和二乙烯三胺五乙酸几乎能完全抑制铁离子催化的抗坏血酸氧化。前一种螯合剂的抑制作用是由于阻止了抗坏血酸对Fe3+的还原，而后一种螯合剂的抑制作用则是由于对这种还原反应以及O2将Fe2+氧化的强烈抑制。这些螯合剂也几乎能完全抑制铜离子催化的抗坏血酸氧化。这些结果表明，阻断金属离子的氧化还原循环对于防止抗坏血酸氧化很重要。
