Substrate specificity of rat sera IgG antibodies with peroxidase and oxidoreductase activities

Abstract

We have recently shown that intact IgGs from the sera of healthy Wistar rats oxidize 3,3'-diaminobenzidine (DAB) in the presence and in the absence of H(2)O(2) similar to horseradish peroxidase (HRP). Here we demonstrate for the first time that the peroxidase and oxidoreductase activities of IgGs can efficiently oxidize not only DAB but also o-phenylendiamine, phenol, p-dihydroquinone, alpha-naphthol, and NADH but, in contrast to HRP, cannot oxidize adrenalin. In contrast to IgGs, HRP cannot oxidize phenol, p-dihydroquinone, or alpha-naphthol in the absence of H(2)O(2). In contrast to plant and mammalian peroxidases, IgGs were more universal in their metal dependence. The specific wide repertoire of polyclonal peroxidase and oxidoreductase IgGs oxidizing various substances could play an important role in protecting the organism from oxidative stress and serve as an additional natural system destroying different toxic, carcinogenic, and mutagenic compounds.

Effect of CoCl2 on the content of different metals and a relative activity of DNA‐hydrolyzing abzymes in the blood plasma of mice

“…In contrast to DNase II (Baranovskii et al ., ), mouse DNase IgGs were not able to catalyze DNA hydrolysis after addition of EDTA or IgG dialysis against EDTA but recovered their activity after the addition of Me 2+ ions (Figure (A)). This result is in an agreement with a small content of Me 2+ ions bound to various polyclonal Abs purified from the sera of human and animals by the standard procedure used in this study (Ikhmyangan et al ., , , ; Polosukhina et al ., ).…”

IgG abzymes with peroxidase and oxidoreductase activities from the sera of healthy humans

“…Application of a set of strict criteria including an analysis of peroxidase and oxidoreductase activities of human IgGs using in situ detection after SDS‐PAGE together with revealing the activity of Fab and F(ab) 2 fragments rules out possible artifacts because of contaminants (Figure ). The most interesting result that in contrast to rat IgGs (Ikhmyangan et al ., , , , ); Tolmacheva et al ., ) is that human IgGs contain not only Me dependent but also Me‐independent subfractions of IgGs with peroxidase and oxidoreductase activities. After Abs extensive dialysis against agents chelating metal ions, the relative peroxidase activity decreased dependently of IgG analyzed from 100 to 10–85%, while oxidoreductase activity from 100 to 14–83% (Table ).…”

“…The data in Table and Figures and demonstrate an extreme diversity of both peroxidase and oxidoreductase activities of human IgGs. Interestingly, these results are in agreement with extreme diversity of peroxidase and oxidoreductase activities of rat IgGs (Ikhmyangan et al ., , , , ); Tolmacheva et al ., ) and the general situation concerning a very high diversity of polyclonal Abzs with various catalytic activities in the sera of AI patients and human milk (Nevinsky and Buneva, ; Nevinsky and Buneva, , ). For example, polyclonal nuclease and polysaccharide‐hydrolyzing Abzs can contain κ or λ light chains, demonstrate the highest activity at various optimal pHs, be activated or not by metal ions, and can be characterized by many different net charges as well as k cat and K m values and by different substrate specificities (Nevinsky and Buneva, ; Nevinsky and Buneva, , ).…”

Systemic lupus erythematosus: molecular cloning of several recombinant DNase monoclonal kappa light chains with different catalytic properties

“…As we have shown in this article, in the absence of externally added metal ions, purified MLChs possess very low activity due to internal metal ions bound to Abs and completely inactive after dialysis against EDTA + EGTA but recovered their activity after the addition of external Me 2+ ions. This result is in an agreement with a small content of Me 2+ ions bound to various polyclonal Abs purified from the sera of human and animals by the standard procedure used in this study (Ikhmyangan et al ., 2005, 2006 a , 2006 b ; Polosukhina et al ., ).…”