Oxidoreductase activities of polyclonal IgGs from the sera of Wistar rats are better activated by combinations of different metal ions

✍ Scribed by Anna S. Tolmacheva; Nataliya P. Zaksas; Valentina N. Buneva; Nataliya L. Vasilenko; Georgy A. Nevinsky

• Publisher: John Wiley and Sons
• Year: 2009
• Tongue: English
• Weight: 429 KB
• Volume: 22
• Category: Article
• ISSN: 0952-3499
• DOI: 10.1002/jmr.923

✦ Synopsis

Abstract

It was shown that IgGs purified from the sera of healthy Wistar rats contain several different bound Me^2+^ ions and oxidize 3,3′‐diaminobenzidine through a H~2~O~2~‐dependent peroxidase and H~2~O~2~‐independent oxidoreductase activity. IgGs have lost these activities after removing the internal metal ions by dialysis against EDTA. External Cu^2+^ or Fe^2+^ activated significantly both activities of non‐dialysed IgGs containing different internal metals (Fe ≥ Pb ≥ Zn ≥ Cu ≥ Al ≥ Ca ≥ Ni ≥ Mn > Co ≥ Mg) showing pronounced biphasic dependencies corresponding to ∼0.1–2 and ∼2–5 mM of Me^2+^, while the curves for Mn^2+^ were nearly linear. Cu^2+^ alone significantly stimulated both the peroxidase and oxidoreductase activities of dialysed IgGs only at high concentration (≥ 2 mM), while Mn^2+^ weakly activated peroxidase activity at concentration >3 mM but was active in the oxidoreductase oxidation at a low concentration (<1 mM). Fe^2+^‐dependent peroxidase activity of dialysed IgGs was observed at 0.1–5 mM, but Fe^2+^ was completely inactive in the oxidoreductase reaction. Mg^2+^, Ca^2+^, Zn^2+^, Al^2+^ and especially Co^2+^ and Ni^2+^ were not able to activate dialysed IgGs, but slightly activated non‐dialysed IgGs. The use of the combinations of Cu^2+^ + Mn^2+^, Cu^2+^ + Zn^2+^, Fe^2+^ + Mn^2+^, Fe^2+^ + Zn^2+^ led to a conversion of the biphasic curves to hyperbolic ones and in parallel to a significant increase in the activity as compared with Cu^2+^, Fe^2+^ or Mn^2+^ ions taken separately; the rates of the oxidation reactions, catalysed by non‐dialysed and dialysed IgGs, became comparable. Mg^2+^, Co^2+^ and Ni^2+^ markedly activated the Cu^2+^‐dependent oxidation reactions catalysed by dialysed IgGs, while Ca^2+^ inhibited these reactions. A possible role of the second metal in the oxidation reactions is discussed. Copyright © 2008 John Wiley & Sons, Ltd.