Co-immobilization of antioxidant enzymes on titania nanosheets for reduction of oxidative stress in colloid systems

Szilárd Sáringer,Paul Rouster,Istvan Szilagyi

doi:10.1016/j.jcis.2021.01.012

Szilárd Sáringer, Paul Rouster + Show 1 more

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https://doi.org/10.1016/j.jcis.2021.01.012

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Abstract

Immobilization of single antioxidant enzyme systems was frequently studied in the past, however, there is a lack of reliable reports on the co-immobilization of such enzymes. Here, an antioxidant enzyme cascade involving superoxide dismutase (SOD) and horseradish peroxidase (HRP) was successfully immobilized on titania nanosheets (TNS) by the sequential adsorption method using poly(diallyldimethylammonium chloride) (PDADMAC) and poly(styrene sulfonate) (PSS) polyelectrolyte building blocks. The development of the cascade system was based on a colloid approach, in which the charging and aggregation processes were optimized in each synthetic step. The polyelectrolyte and enzyme multilayers were built up in two different sequences at the particle interface, namely, TNS-PDADMAC-SOD-PSS-HRP and TNS-HRP-PDADMAC-SOD-PSS. The formation of the polyelectrolyte layers led to charge reversal of the carrier and the saturated PDADMAC and PSS layers stabilized the dispersions, in particular, their resistance against salt-induced aggregation was especially excellent. The results of enzymatic assays revealed that the SOD and HRP-like activities of the composites depended on the location of the enzymes in the hybrid material. The obtained compounds showed remarkable antioxidant effect and were able to simultaneously decompose superoxide radical anions and hydrogen peroxide. The cascade systems are of great promise in industrial manufacturing processes during the preparation of high-quality products without any damages by reactive oxygen species.

Highlights

Immobilization of single antioxidant enzyme systems was frequently studied in the past, there is a lack of reliable reports on the co-immobilization of such enzymes
The use of polyelectrolytes allows the use of the sequential adsorption method [34] as a possible enzyme immobilization technique, which has already been applied on planar surfaces to embed proteins between polyelectrolyte layers [35,36,37]
Note that the immobilization of single superoxide dismutase (SOD) [18] and horseradish peroxidase (HRP) [20] on titania nanosheets (TNS) has been reported earlier, while the present study focuses on their co-immobilization

Summary

Introduction

Immobilization of single antioxidant enzyme systems was frequently studied in the past, there is a lack of reliable reports on the co-immobilization of such enzymes. The latter ones, including superoxide dismutase (SOD) [7] and horseradish peroxidase (HRP) [8], are the most effective substances to combat oxidative stress, i.e., SOD dismutates O2À to molecular oxygen and H2O2, while HRP consumes H2O2 in oxidation reactions They act together as an enzyme cascade in the cellular environments [9]. Concerning the antioxidant enzymes, immobilization of single proteins including SOD [17,18,19] and HRP [20,21,22] on various substrates was frequently reported in the past Coimmobilization of such enzymes could be an appropriate mimic of the cellular environment, where ROS are decomposed to molecular oxygen and water in tandem reactions catalyzed by the enzymes. There is a lack of studies dealing with the coimmobilization of enzymes on nanoparticulate supports applying the polyelectrolyte-based sequential adsorption technique

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