Heterologous Expression, Purification and Characterization of a Peroxidase Isolated from Lepidium draba

Exploring the impact of taurine on the biochemical properties of urate oxidase: response surface methodology and molecular dynamics simulation

This paper investigates the impact of taurine as an additive on the structural and functional stability of urate oxidase. First, the effect of the processing parameters for the stabilization of Urate Oxidase (UOX) using taurine was examined using the response surface methodology (RSM) and the central composite design (CCD) model. Also, the study examines thermodynamic and kinetic parameters as well as structural changes of urate oxidase with and without taurine. Fluorescence intensity changes indicated static quenching during taurine binding. The obtained result indicates that taurine has the ability to preserve the native structural conformation of UOX. Furthermore, molecular dynamics simulation is conducted in order to get insights into the alterations in the structure of urate oxidase in the absence and presence of taurine under optimal conditions. The molecular dynamics simulation section investigated the formation of hydrogen bonds (H-bonds) between different components as well as analysis of root mean square deviation (RMSD), root mean square fluctuations (RMSF) and secondary structure. Lower Cα-RMSD and RMSF values indicate greater stabilization of the taurine-treated UOX structure compared to the free enzyme. The results of molecular docking indicate that the binding of taurine to the UOX enzyme through hydrophobic interactions is associated with a negative value for the Gibbs free energy.

Recombinant Lignin Peroxidase with Superior Thermal Stability and Melanin Decolorization Efficiency in a Typical Human Skin-Mimicking Environment

Recently, the desire for a safe and effective method for skin whitening has been growing in the cosmetics industry. Commonly used tyrosinase-inhibiting chemical reagents exhibit side effects. Thus, recent studies have focused on performing melanin decolorization with enzymes as an alternative due to the low toxicity of enzymes and their ability to decolorize melanin selectively. Herein, 10 different isozymes were expressed as recombinant lignin peroxidases (LiPs) from Phanerochaete chrysosporium (PcLiPs), and PcLiP isozyme 4 (PcLiP04) was selected due to its high stability and activity at pH 5.5 and 37 °C, which is close to human skin conditions. In vitro melanin decolorization results indicated that PcLiP04 exhibited at least 2.9-fold higher efficiency than that of well-known lignin peroxidase (PcLiP01) in a typical human skin-mimicking environment. The interaction force between melanin films measured by a surface forces apparatus (SFA) revealed that the decolorization of melanin by PcLiP04 harbors a disrupted structure, possibly interrupting π-π stacking and/or hydrogen bonds. In addition, a 3D reconstructed human pigmented epidermis skin model showed a decrease in melanin area to 59.8% using PcLiP04, which suggests that PcLiP04 exhibits a strong potential for skin whitening.

Application of exogenous glutathione decreases chromium translocation and alleviates its toxicity in soybean (Glycine max L.)

Chromium is considered one of the most severe toxic elements affecting agriculture. Soybean seedlings under chromium stress were treated with glutathione and buthionine sulfoximine. The effects of exogenous glutathione on the physiological effects of two different chromium-resistant soybean seedlings and the expression levels of expression levels related genes were studied. This study tested the seedling weight and SPAD values, detected enzymatic antioxidants (i.e., superoxide dismutase, peroxidase, catalase, catalase, ascorbate peroxidase), and non-enzymatic antioxidants (i.e., glutathione, proline, soluble sugars, and soluble phenols) that attenuate chromium-induced reactive oxygen species, and quantified several genes associated with glutathione-mediated chromium stress. The results showed that exogenous glutathione could improve the physiological adaptability of soybean seedlings by regulating photosynthesis, antioxidant, and related enzyme activities, osmotic system, the compartmentalization of ion chelation, and regulating the transcription level of related genes, thereby increasing the chromium accumulation of soybean seedlings, enhancing the tolerance of chromium stress, and reducing the toxicity of chromium. Overall, the application of glutathione alleviates chromium toxicity in soybeans, and this strategy may be a potential farming option for soybean bioremediation in chromium-contaminated soils.

Modeling and optimization of radish root extract drying as peroxidase source using spouted bed dryer

The main advantages of the dried enzymes are the lower cost of storage and longer time of preservation for industrial applications. In this study, the spouted bed dryer was utilized for drying the garden radish (Raphanus sativus L.) root extract as a cost-effective source of the peroxidase enzyme. The response surface methodology (RSM) was used to evaluate the individual and interactive effects of main parameters (the inlet air temperature (T) and the ratio of air flow rate to the minimum spouting air flow rate (Q)) on the residual enzyme activity (REA). The maximum REA of 38.7% was obtained at T = 50 °C and Q = 1.4. To investigate the drying effect on the catalytic activity, the optimum reaction conditions (pH and temperature), as well as kinetic parameters, were investigated for the fresh and dried enzyme extracts (FEE and DEE). The obtained results showed that the optimum pH of DEE was decreased by 12.3% compared to FEE, while the optimum temperature of DEE compared to FEE increased by a factor of 85.7%. Moreover, kinetic parameters, thermal-stability, and shelf life of the enzyme were considerably improved after drying by the spouted bed. Overall, the results confirmed that a spouted bed reactor can be used as a promising method for drying heat-sensitive materials such as peroxidase enzyme.

Recombinant Expression and Characterization of Lemon (Citrus limon) Peroxidase

BACKGROUND

Class III plant peroxidases play important role in a number of physiological processes in plants such as lignin biosynthesis, suberization, cell wall biosynthesis, reactive oxygen species metabolism and plant defense against pathogens. Peroxidases are also of significance in several industrial applications. In view of this, the production and identification of novel peroxidases having resistance towards temperature, pH, salts is desirable.

OBJECTIVE

The objective of the present work was to clone and characterize a novel plant peroxidase suitable for industrial application.

METHODS

A full length cDNA clone of lemon peroxidase was isolated using PCR and RACE approaches, characterized and heterologously expressed in Escherichia coli using standard protocols. The expressed peroxidase was purified using Ni-NTA agarose column and biochemically characterized using standard protocols. The peroxidase was also in-silico characterized at nucleotide as well as protein levels using standard protocols.

RESULTS

A full length cDNA clone of lemon peroxidase was isolated and expressed heterologously in E. coli. The expressed recombinant lemon peroxidase (LPRX) was activated by in-vitro refolding and purified. The purified LPRX exhibited pH and temperature optima of pH 7.0 and 50°C, respectively. The LPRX was found to be activated by metal ions (Na+, Ca2+, Mg2+ and Mn2+) at lower concentration. The expressional analysis of the transcripts suggested involvement of lemon peroxidase in plant defense. The lemon peroxidase was in silico modelled and docked with the substrates guaiacol, and pyrogallol and shown the favourability of pyrogallol over guaiacol, which is in agreement with the in-vitro findings. The protein function annotation analyses suggested the involvement of lemon peroxidase in the phenylpropanoid biosynthesis pathway and plant defense mechanisms.

CONCLUSION

Based on the biochemical characterization, the purified peroxidase was found to be resistant towards the salts and thus, might be a good candidate for industrial exploitation. The in-silico protein function annotation and transcript analyses highlighted the possible involvement of the lemon peroxidase in plant defense response.

Immobilization of Lepidium draba peroxidase on a novel Zn-MOF nanostructure

In the present study, ultrasound irradiation was utilized to synthesize a novel zinc metal-organic framework (MOF). Scanning electron microscopic images, exhibited homogenous morphology with a nano-sized distribution of the Zn-MOF structure as also confirmed by X-ray diffraction patterns. Following, physical immobilization of Lepidium draba peroxidase (LDP) were optimized on the Zn-MOF in phosphate buffer (50 mM, pH 6.5), ratio amount of MOF/enzyme; 7/1 after shaking for 15 min at 25 °C, with high protein loading of 109.9 mg/g and immobilization yield of 93.3%. Immobilized enzyme (IE) exhibited more than 330% enhanced specific activity and also exhibited more than 150% specific affinity to its substrate (3,3',5,5'-tetramethylbenzidine) with respect to the free enzyme (FE). Optimum temperature of the IE was obtained at 20 °C while its was 25 °C for the FE, and thermostability of the IE augmented at temperature of 30 °C and 40 °C by the factors of 104 and 108% respectively. pH stability under neutral and basic condition and storage stability of the IE improved with respect to the FE as well as its structural stability (T_m; 73 °C for IE vs. 63 °C for FE). Furthermore, immobilization is accompanied with alteration on the enzyme structure as revealed by the intrinsic and extrinsic fluorescence spectra.

Scalable High-Performance Production of Recombinant Horseradish Peroxidase from E. coli Inclusion Bodies

Horseradish peroxidase (HRP), an enzyme omnipresent in biotechnology, is still produced from hairy root cultures, although this procedure is time-consuming and only gives low yields. In addition, the plant-derived enzyme preparation consists of a variable mixture of isoenzymes with high batch-to-batch variation preventing its use in therapeutic applications. In this study, we present a novel and scalable recombinant HRP production process in Escherichia coli that yields a highly pure, active and homogeneous single isoenzyme. We successfully developed a multi-step inclusion body process giving a final yield of 960 mg active HRP/L culture medium with a purity of ≥99% determined by size-exclusion high-performance liquid chromatography (SEC-HPLC). The Reinheitszahl, as well as the activity with 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) and 3,3',5,5'-tetramethylbenzidine (TMB) as reducing substrates, are comparable to commercially available plant HRP. Thus, our preparation of recombinant, unglycosylated HRP from E. coli is a viable alternative to the enzyme from plant and highly interesting for therapeutic applications.

Improvement of kinetic properties and thermostability of recombinant Lepidium draba peroxidase (LDP) upon exposed to osmolytes

In this study, effects of different concentrations of glycine and D-sorbitol were analyzed on the activity and thermostability of recombinant Lepidium draba peroxidase (LDP). Based on the results, activity of the enzyme increased in the presence of various concentrations of these osmolytes. Maximum activity was detected for the enzyme in the presence of 300 mM glycine and 600 mM sorbitol. In presence of the aforementioned doses of osmolytes, enzyme affinity for substrate (3,3',5,5'-tetramethylbenzidine and H₂O₂) and V_max increased. According to the results, enzyme stability improved against temperature and H₂O₂. Furthermore, structural changes of the enzyme upon exposure to the osmolytes were revealed by the use of far-UV circular dichroism and fluorescence methods. The results showed, whereas the secondary structure of the enzyme was not significantly changed upon exposed to the osmolytes, the fluorescence studies revealed microenvironment of the aromatic residues dramatically affected by them. Overall, it may be speculated, structural changes of the enzyme upon exposed to the osmolytes, lead to the improvement of its kinetic properties and stability that can be benefit for using of it in in vitro applications.