Synthesis of copper ion incorporated horseradish peroxidase-based hybrid nanoflowers for enhanced catalytic activity and stability

Abstract

In this study, we report the preparation, catalytic activity and stability of a hybrid nanoflower (hNF) formed from horseradish peroxidase (HRP) enzyme and copper ions (Cu(2+)). We studied the morphology of hNFs as a function of the concentrations of copper (Cu(2+)) ions, chloride ions (Cl(-)) and HRP enzyme, the pH of the buffer solution (phosphate buffered saline), and the temperature of the reaction. The effects of morphology on the catalytic activity and stability of hNFs were evaluated by oxidation of guaiacol (2-methoxyphenol) to colored 3,3-dimethoxy-4,4-diphenoquinone in the presence of hydrogen peroxide (H2O2). The enhanced activity of hNFs synthesized (from 0.02 mg mL(-1) HRP in 10 mM PBS (pH 7.4) at +4 °C) was 17 595 U mg(-1), which was ∼300% higher than free HRP in PBS, where it achieved an activity of 5952 U mg(-1). In terms of stability, these hNFs stored in PBS buffer at +4 °C and room temperature (RT = 20 °C) lost 4% and 20%, respectively, of their initial catalytic activities within 30 days. Finally, we demonstrated that these hNFs can be utilized as sensors for the detection of dopamine.

A new generation approach in enzyme immobilization: Organic-inorganic hybrid nanoflowers with enhanced catalytic activity and stability

“…And also, we showed enhanced catalytic activity and stability of nanoflower toward oxidation of guaiacol (2-methoxyphenol) to colored 3, 3-dimethoxy-4, 4-diphenoquinone in the presence of hydrogen peroxide (H2O2) (Fig. 5) [45].…”

“…Inspiring from Zare and coworkers, several research groups studied the preparation and characterization of organic-inorganic hybrid nanoflowers using different enzymes and metal ions for different purposes [42][43][44][45][46][47][48][49]. In one of our study, we determined how the experimental parameters, such as concentrations of copper (Cu 2+ ) ions, chloride ions (Cl -) and HRP enzyme; the pH of the buffer solution (phosphate buffered saline); and the temperature of the reaction, affect the morphology and activity performance of synthesized nanoflowers.…”

Self-assembled organic⿿inorganic hybrid glucoamylase nanoflowers with enhanced activity and stability

“…Also, hybrid glucoamylase nanoflowers showed 2.38, 2.21 and 1.90 folds increased half-life with respect to free glucoamylase at 50, 60 and 70°C respectively. Enhanced thermal stability indicates that glucoamylase nanoflowers need more time to denature by heat as compared to their free form [28][29][30][31][32][33][34][35].…”

“…While below and above this isoelectric point, the enzyme is expected to be positive and negative, respectively. At lower pH values (3.5, 4.5 and 5.5 pH values adjusted with HCl) below the pI, very strong repulsions between protonated positively charged enzyme molecules and Cu 2+ ions were observed which led to no blue coloured precipitates [29].…”

Formation of Functional Nanobiocatalysts with a Novel and Encouraging Immobilization Approach and Their Versatile Bioanalytical Applications

“…In terms of inorganic component, some metal ions including copper (II), iron (II), calcium have been used as inorganic part of nanoflower [38][39][40][41][42][43][44][45][46][47]. A wide range of enzymes containing commercially available and isolated from the plants, HRP [38,39,40], SBP [41], alfa-chymotypsin [42], laccase [43,48], urease [44], lactoperoxidase [45], lipase [46], Turkish black radish peroxidase [47], have been successfully incorporated into the nanoflower synthesis. The nanoflowers have provided variety of applications such as, calorimetric sensors to detect H2O2, phenol [38], dopamine [39,45], epinephrine [43,45], dye decolorization [47,48], and protein digestion [42].…”