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This study focuses on the immobilization of horseradish peroxidase (HRP) on modified acrylic fabrics incorporating gold and silver nanoparticles. The process involves treating the acrylic fabrics with hydroxylamine hydrochloride and then coating them with silver and gold nanoparticles. Both obtained materials, treated acrylic fabrics-coated with silver nanoparticles (AgNPs@TA-HAC) and treated acrylic fabrics-coated with gold nanoparticles (AuNPs@TA-HAC), were utilized as supporters for HRP. The physicochemical properties of modified acrylic fabrics were investigated using FTIR, SEM, and zeta potential. HRP immobilized on AgNPs@TA-HAC displayed an activity of 69 units/g support with a specific activity of 4.55 units/mg protein, whereas HRP immobilized on AuNPs@TA-HAC demonstrated an activity of 76 units/g support with a specific activity of 4.75 units/mg protein. After the 15 repetitive cycles, the immobilized HRP on AuNPs@TA-HAC and AgNPs@TA-HAC retained 75 and 59% of their enzymatic activity, respectively. The immobilized HRP on both material supporters retained its activity better compared to the free HRP when exposed to all tested organic solvents. The Michaelis constant (Km) for free HRP and HRP immobilized on AuNPs@TA-HAC and AgNPs@TA-HAC were determined to be 6.23, 8.65, and 9.11 mM, respectively. The maximum reaction rates (Vmax) for the immobilized HRP on both supports were slightly reduced at 0.71 and 0.69 U/mL, compared to 0.74 U/mL for free HRP. This approach of utilizing acrylic fabrics and metal nanoparticles provides a promising method for enzyme immobilization, with potential applications in various industries. [ABSTRACT FROM AUTHOR]

Alginate is a biomaterial that is considered suitable for enzyme immobilization. The biocompatibility and characteristics of the immobilized system can be improved by combining alginate with magnetite Fe3O4 nanoparticles. Therefore, the current study investigated the effect of magnetite Fe3O4 NPs on urease immobilization using different concentrations of magnetite Fe3O4 NPs. The morphological features for alginate/magnetite Fe3O4 NPs before and after immobilization were studied using an SEM, TGA, and FTIR. The reusability, half-life, enzymatic kinetics, and storage stability of the enzyme were all enhanced. The immobilization efficiency was determined to be 91% at optimal conditions. The immobilized urease was reused 20 times and a recovery of 59% of the initial activity. The soluble and immobilized urease was stored at 4 °C for 12 weeks and preserved 13% and 49% of the initial activities, respectively. The optimum pH for soluble and immobilized urease activity was estimated to be 7. The optimum temperature for soluble and immobilized urease activity was found to be 35 °C and 40 °C, respectively. The kinetics parameters showed the Vmax of 4.4 and 3.1 μmol/ml·min and the Km of 49.5 and 54.6 mM for the soluble and immobilized urease, respectively. Immobilized urease had a half-life of 11–20 min. The activation energy (Ea) of immobilized urease was determined to be 32 kJ K−1 mol−1, indicating that a small quantity of energy is required to produce the activated complex of substrate hydrolysis. [ABSTRACT FROM AUTHOR]

Modified polymer design has attracted significant attention for enzyme immobilization, offering promising applications. In this study, amine-terminated polymers were synthesized by incorporating functional groups into polyacrylonitrile using hexamethylenediamine. This work highlights the successful enzyme immobilization strategy using modified polymers, offering improved stability and expanded operational conditions for potential biotechnological applications. The resulting amino groups were utilized to capture silver ions, which were subsequently converted to silver nanoparticles (AgNPs). The obtained materials, AgNPs@TA-HMDA (acrylic textiles coated silver nanoparticles AgNPs) and Ag(I)@TA-HMDA (acrylic textiles coated with Ag ion) were employed as supports for β-glucosidase enzyme immobilization. The highest immobilization yields (IY%) were achieved with AgNPs@TA-HMDA at 92%, followed by Ag(I)@TA-HMDA at 79.8%, resulting in activity yields (AY%) of 81% and 73%, respectively. Characterization techniques such as FTIR, FE-SEM, EDX, TG/DTG, DSC, and zeta potential were employed to investigate the structural composition, surface morphologies, elemental composition, thermal properties, and surface charge of the support materials. After 15 reuses, the preservation percentages decreased to 76% for AgNPs@TA-HMDA/β-Glu and 65% for Ag(I)@TA-HMDA/β-Glu. Storage stability revealed that the decrease in activity for the immobilized enzymes was smaller than the free enzyme. The optimal pH for the immobilized enzymes was broader (pH 5.5 to 6.5) compared to the free enzyme (pH 5.0), and the optimal temperature for the immobilized enzymes was 60 °C, slightly higher than the free enzyme's optimal temperature of 50 °C. The kinetic analysis showed a slight increase in Michaelis constant (Km) values for the immobilized enzymes and a decrease in maximum velocity (Vmax), turnover number (Kcat), and specificity constant (Kcat/Km) values compared to the free enzyme. Through extensive characterization, we gained valuable insights into the structural composition and properties of the modified polymer supports. This research significantly contributes to the development of efficient biotechnological processes by advancing the field of enzyme immobilization and offering valuable knowledge for its potential applications. [ABSTRACT FROM AUTHOR]

The evolution of green technology for the simple and ecological formation of silver nanoparticles (AgNPs) inspired the present work for simple and efficient detection of reducing sugars (RS) in foods. The proposed method relies on gelatin as the capping and stabilizing agent and the analyte (RS) as the reducing agent. This work may attract significant attention, especially in the industry, for testing the sugar content using gelatin-capped silver nanoparticles as it not only detects the sugar in food, but also determines the content (%), which could be an alternative technique to the conventionally used DNS colorimetric method. For this purpose, a certain amount of maltose was mixed with a gelatin-silver nitrate. Different conditions that may affect the color changes at 434 nm owing to the in situ formed AgNPs, such as gelatin-silver nitrate ratio, PH, time, and temperature, have been investigated. The 1:3 mg/mg ratio of gelatin-silver nitrate dissolved in 10 mL distilled water was most effective in color formation. The development of AgNPs color increases within 8–10 min at PH 8.5 as the selected optimum value and at the optimum temperature of 90 °C for the evolution of the gelatin-silver reagent's redox reaction. The gelatin-silver reagent showed a fast response (less than 10 min) with a detection limit for maltose at 46.67 µM. In addition, the selectivity of maltose was checked in the presence of starch and after its hydrolysis with α-amylase. Compared with the conventionally used dinitrosalicylic acid (DNS) colorimetric method, the proposed method could be applied to commercial fresh apple juice, watermelon, and honey to prove its viability for detecting RS in fruits; the total reducing sugar content was 287, 165, and 751 mg/g, respectively. [ABSTRACT FROM AUTHOR]

Worldwide, human beings have traditionally employed many folkloric herbal resources as complementary and alternative remedies, and these remedies have played a pivotal role in modern medicines for many decades, as scientists have used them to develop drugs. We studied the effects of employing solvents with varying polarity on the yields of phytochemical components extracted from the plant Rhazya stricta. We used chloroform–methanol (1:1), methanol, ethanol, diethyl ether, and ethyl acetate as extraction solvents. The results showed that the efficiencies of the solvents at extracting phytochemical compounds were in this order: chloroform–methanol < ethanol < methanol < diethyl ether < ethyl acetate extract. The chloroform–methanol extract produced the highest concentration of phenolic and flavonoid contents among the five solvents tested (13.3 mg GAE/g DM and 5.43 CE/g DM). The yields of the extracted phytochemical compounds ranged from 47.55 to 6.05%. The results revealed that the properties of the extraction solvents considerably impacted the extraction yield and the phytochemical components of the R. stricta extract. Furthermore, compared with the other solvents, the chloroform–methanol extraction led to the highest yield (47.55%) and to more phytochemical substances being extracted. The aim of this study is to investigate the phytochemical compounds extracted from R. stricta with different solvents that have different polarities. [ABSTRACT FROM AUTHOR]

Lipases are extensively utilized industrial biocatalysts that play an important role in various industrial and biotechnological applications. Herein, polyacrylonitrile (PAN) was treated with hexamethylene diamine (HMDA) and activated by glutaraldehyde, then utilized as a carrier support for Candida rugosa lipase. In this regard, the morphological structure of modified PAN before and after the immobilization process was evaluated using FTIR and SEM analyses. The immobilized lipase exhibited the highest activity at pH 8.0, with an immobilization yield of 81% and an activity of 91%. The optimal pH and temperature for free lipase were 7.5 and 40 °C, while the immobilized lipase exhibited its optimal activity at a pH of 8.0 and a temperature of 50 °C. After recycling 10 times, the immobilized lipase maintained 76% of its activity and, after 15 reuses, it preserved 61% of its activity. The lipase stability was significantly improved after immobilization, as it maintained 76% of its initial activity after 60 days of storage. The calculated Km values were 4.07 and 6.16 mM for free and immobilized lipase, and the Vmax values were 74 and 77 μmol/mL/min, respectively. These results demonstrated that synthetically modified PAN is appropriate for immobilizing enzymes and has the potential for commercial applications. [ABSTRACT FROM AUTHOR]

Nanoparticles are increasingly utilized as coating materials to improve the properties of polyester textiles. In this work, polyester textiles were successfully fabricated, with hydrazide groups serving as ligands for the entrapment of sliver ions and subsequent reduction to AgNPs. Polydopamine (PDA) was used in this work to impart antibacterial and antioxidant properties to the polyester textiles through its phenolic hydroxyl groups, which can convert silver ions into AgNPs. Moreover, glucose was used as a reducing agent to create AgNPs-loaded polyester hydrazide. ATR-FTIR, SEM, EDX, thermogravimetric analysis (TGA), and tensile strength were used to characterize the pristine polyester, the polyester hydrazide, the PDA-coated AgNP-loaded polyester hydrazide and the AgNP-loaded polyester hydrazide. A broth test was also used to investigate the textile's antimicrobial activities against Escherichia coli and Staphylococcus aureus. Overall, the composite nanocoating with PDA-AgNPs demonstrated good tensile strength and antioxidant and antibacterial characteristics, implying the practicality of PDA-AgNPs coating polyester for biomedical textile applications. [ABSTRACT FROM AUTHOR]

The emergence of superbugs and resistant pathogens poses a challenge in scientific and medical research as they threaten public health worldwide. Many herbal natural products currently used in therapies have been suggested to exert antimicrobial, antiviral and even virucidal activities against a vast majority of impervious pathogens. Rhazya stricta, a folk medicinal desert plant from Saudi Arabia was recently revealed to exhibit bactericidal activity against multidrug-resistant (MDR) microorganisms. The pandemic caused by the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) is a threat to public health worldwide. Hence, we examined the antiviral activity of R. stricta against the virus. The R. stricta water extract was prepared at the traditional dose. The antagonistic effects of this extract against pathogens have been proven in previous studies, and those against SARS-CoV-2 were shown in the present study. Therefore, we explored the effects of the plant extracts and fractions against the virus for future drug development. All plant extracts showed antiviral effects against SARS-CoV-2 in the Vero E6 cell lines. Non-alkaloids showed the strongest effect against the virus, followed by weak base alkaloids and finally strong base alkaloids. A cytotoxicity assay was performed to explore the safest dose with the strongest antiviral effects. The non-alkaloid extract derived from R. stricta leaves is a promising antiviral candidate for the development of potential drugs with appropriate activity against COVID-19 and other life-threatening diseases. [ABSTRACT FROM AUTHOR]

We used two types of Ocimum basilicum plants and white light-emitting diode (LED) lights as controls (plant factory unit 1, PFU 1). We applied four composite LED light treatments, 125:125:125 white, red, blue (PFU 2), 0.0:250:125 white, red, blue (PFU 3), 125:125:57 white, red, blue (PFU 4) and 125:57:125 white, red, blue (PFU 5) to evaluate light quality effects on antioxidant capacity of O. basilicum plants. The results revealed that the composite lights of PFUs 2,3,4 and 5 were beneficial for the accumulation of flavonoids and glutathione but were not beneficial forthe proanthocyanidin content; the plants subjected to the PFUs 2,3,4 and 5 treatments had a higher laccase activity and proline content and a lower malondialdehyde (MDA) content, polyphenol oxidase activity and peroxidase activity than the control plants.Analysis via high-performance liquid chromatography revealed that protocatechuic acid, gentisic acid, chlorogenic acid, syringic acid, cinnamic acid, quercetin, apigenin, kaempferol, chrysin, p-hydroxybenzoic acid, p-coumaric acid, apigenin-7-glucoside, rutin, rosmarinic acid were the major phenolic components in the O. Basilicum extracts, and sufficient composite lighting of O. basilicum plants significantly enhanced these antioxidant concentrations. Our results indicate that the use of LEDs with different light qualities to irradiate O. basilicum significantly improved the antioxidant capacity which could be a beneficial for nutrition and health benefits. [ABSTRACT FROM AUTHOR]

A total of 13 Actinomycetes strains were isolated from 70 soil samples collected from five locations across the Jeddah Province, while the other two locations located in Baljurashi province of Saudi Arabia. All 13 isolates were purified and subjected to enzymatic screening and antibacterial assays. The results indicated that two of these isolates (AC45 and AC69) produced both enzymes and exerted some antibacterial activity. Isolate AC45 produced more amylase and polygalacturonase (697.8 and 1498.59 units/ml, respectively) than isolate AC69; however, AC69 secreted more lipase than AC45 (6957 and 22127 unit/ml, respectively). Furthermore, both AC45 and AC69 exhibited good antibacterial activity against Staphylococcus aureus, Staphylococcus epidermidis, and Bacillus subtilis. The two isolates were identified using their 16S rRNA sequences, and the results suggest that isolate AC45 shares 99.71% similarity with Streptomyces lavenduligriseus and isolate AC69 shares 99% similarity with Streptomyces sp. [ABSTRACT FROM AUTHOR]

Lyophilized aqueous extracts of sugarcane juice (SJ), vacuum pan jaggery (VJ), and open pan jaggery (OJ) were estimated for their Physico-chemical properties, phytochemical constituents, and biological activity against certain clinical isolates. The phytochemical results of flavonoid and tannin content indicated high significance in the mean values of the VJ sample whereas, phenol and terpenoid content was significantly higher in the OJ sample. For antioxidant activity, the mean values of IC50 of DPPH assay and ABTS assay showed a highly significant increase for OJ, which were 2.810 and 2.441% respectively. All the aqueous extract showed a zone of inhibition against tested organism extract except Salmonella typhi. Bacillus subtilis, and Pseudomonas aeruginosa. The results indicate that the Lyophilized SJ, VJ and OJ have phytochemical components that can have other clinical and medicinal properties that use these products not only as a food additive but as pharmaceutical additives. Worth a mention that our study constitutes the first research to evaluate vacuum evaporated jaggery product as a potential antioxidant resource to investigate by in vitro trials in cellular systems. [ABSTRACT FROM AUTHOR]

Herein, the immobilization of α–amylase onto hydroxyapatite (HA) and hydroxyapatite-decorated ZrO 2 (10%wt) (HA-ZrO 2) nanocomposite were investigated. The immobilization yield was 69.7% and 84% respectively. The structural differences were characterized using X-Ray diffraction, attenuated total reflectance-Fourier transform infrared spectra, Raman, and scanning electron microscope. After 10 repeated cycles, the residual activity of immobilized α–amylase onto HA and HA-ZrO 2 nanocomposite was 46% and 70%, respectively. The storage stability was recorded to be 27%, 50% and 69% from its initial activity in the case of free and immobilized enzyme onto HA and HA-ZrO 2 nanocomposite, respectively after 8 weeks. The pH-activity profile and temperature revealed pH 6.0 and temperature 50 °C as the optimal values of free α-amylase, while the optimum values for α-amylase on HA and HA-ZrO 2 was shifted to pH 6.5 and 60 °C after immobilization. The immobilized α-amylase onto HA-ZrO 2 showed comparatively higher catalytic activity than the free α-amylase. The K m value after the immobilization process onto HA was 2.1 folds highly than that of the free enzyme. In conclusion, it can be inferred that HA-ZrO 2 is more sustainable and beneficial support for enzyme immobilization and it represents promising supports for different uses of α–amylase in the biomedical applications. • Ionic bond immobilization of α-amylase onto hydroxyapatite and hydroxyapatite-decorated (10%wt.) ZrO 2 was investigated. • Immobilization was confirmed by SEM, EDX, XRD, FT-IR, and Raman microscopy. • Immobilized α-amylase preparations maintained and enhanced biochemical properties of the free enzyme. [ABSTRACT FROM AUTHOR]

In this study, Arabian balsam α-amylase was purified using the three-step purification method with 9.8-fold purification and 7% recovery. The purified α-amylase's molecular weight was 85 kDa. Calcium alginate incorporated with iron (III) oxide nanoparticles was applied as an immobilizing support for α-amylase. The immobilized α-amylase was characterized by Fourier transform infrared spectroscopy, thermogravimetric analysis, and scanning electron microscopy. In addition, the optimum conditions for immobilization efficiency, immobilization time, reusability, kinetic parameters, and the effect of pH for the immobilization process were examined. After storage, about 87% of the initial activity was maintained at 4 °C for 60 days. The immobilized enzyme exhibited enhanced stability compared to the soluble enzyme in relation to pH and temperature. The immobilized enzyme provided the following kinetic variables: 0.455 mg/mL, 4050 s−1, 28.57 μmol maltose/mL, and 8900 s−1 mg−1 mL for Km, kcat, Vmax, and kcat/Km, respectively, compared with 1.798 mg/mL, 5980 s−1, 42.19 μmol maltose/mL, and 3326 s−1 mg−1 mL for the soluble enzyme. The total phenolic contents of the soluble and immobilized α-amylase-treated wheat kernels were increased by 1.26 and 1.31 fold, respectively. Purified α-amylase from Arabian balsam can thus be successfully used to enhance the antioxidant capacity of cereals. • α-Amylase was isolated and purified from Arabian balsam stems with a molecular weight of 85 kDa. • The α-amylase was successfully immobilized onto a calcium alginate/Fe 2 O 3 nanocomposite beads. • The immobilization method was improved the operational activity of α-amylase. • The immobilized enzyme was recyclable for 10 times. [ABSTRACT FROM AUTHOR]

Polygalacturonases (PGs) are necessary to degrade the insoluble viscous pectin components during the clarification process of fruit juice and are produced by some plants and various microbes, such as bacteria, yeasts and fungi. In this study, an exo-polygalacturonase (exo-PGP4a) was purified from T. Pseudokoningii using DEAE-Sepharose and Sephacryl S-200 columns. We show that the enzyme produced in this study by solid-state fermentation of citrus Orange peel was purified 20-fold with 12.8% recovery. The apparent molecular mass of the enzyme was determined to be 25 kDa using gel filtration and SDS-PAGE. The optimum temperature and pH of the exo-PGP4a were 45°C and 6, respectively. The exo-PGP4a showed half-lives of 50.95 and 21.32 min at 55 and 75°C, respectively. The activation energy for denaturation (Ea*) was 42.596 kJ/mol. The Km value of the enzyme for PGA hydrolysis was 2 mg/ml, and the Vmax was 3.27 µmol min-1 mg1 . Several metal cations, such as Cu2+and Zn2+, were found to enhance the enzymatic activity of the exo-PGP4a, while Pb2+, Ca2+, Ni2+, Cd2+, Co2+ and Hg2+ ions were found to be inhibitory. In this study, we suggest the exo-polygalacturonase has potential role of the clarification of Orange, Apple, Grape, and Peach juices in the food industry. [ABSTRACT FROM AUTHOR]

Commiphora gileadensis is commonly used in Saudi Arabia for oral hygiene. A lack of data about its biological activity encouraged us to evaluate the antioxidant and antibacterial activities of its leaf and stem extracts. Ethanol, methanol, acetone and deionized water were tested as extraction solvents. 80% methanol gave the highest extracted concentrations of phenolic and flavonoid substances. The leaf and stem extracts were respectively evaluated for their radical scavenging activity with DPPH (EC50 = 3.39, and 1.06), ABTS (EC50 = 0.690, and 0.55), and peroxide scavenging activity (EC50 = 2.43, and 1.28). GC-MS identified a wide range of compounds that may be responsible for these activities of the results observed. The highest levels of chlorophyll, carotenoids, and lycopene were found in the leaf extract while level of proanthocyanidins was found in the stem peels extract. The peroxidase and catalase activities of stem peel extract were higher than those of the leaf extract. The findings showed that the leaf and stem peel extracts of C. gileadensis exhibited significant antibacterial activity against the test organisms. The minimum inhibitory concentrations for the plant extracts were compared with the standard reference drug Augmentin but the time–kill curves for the C. gileadensis extracts showed that they were less effective than Augmentin. Moreover, the stem peel extract exhibited stronger antibacterial activity than the leaf extract. In conclusion, C. gileadensis can be an important source of natural antioxidants, used as a healthy chewing stick for teeth brushing and oral hygiene purposes. [ABSTRACT FROM AUTHOR]

In this study, hydrazine treated acrylic fabrics (polyacrylonitrile, PAN) activated with cyanuric chloride was developed as supporting material for horseradish peroxidase (HRP) immobilization. The immobilization of HRP onto the modified supporting material was achieved after being end-over-end incubated for 12 h. Field emission scanning electron microscopy and Fourier-transform infrared spectroscopy techniques were used to confirm the successful immobilization. Reusability experiment was performed to estimate the ability of the immobilized HRP to recover the reaction medium, in which it was observed to retain 78% of its original activity after 10 cycles. Relative to the soluble HRP, the optimum pH and temperature for the immobilized HRP were shifted to 7–7.5 and 50 °C, respectively. The kinetic parameters of guaiacol and H 2 O 2 for the immobilized HRP were determined to be Km/Vmax = 57.61, 11.35 and Kcat/Km = 1.87, 1.86, respectively, while the values for the free form were Km/Vmax = 41.49, 6.23 and Kcat/Km = 1.87, 1.86, respectively. Compared to the soluble form, the immobilized HRP exhibited higher resistance toward metal ions and some organic solvents. For an application perspective. The immobilization of HRP using this procedure has the potential to be used for industrial application and wastewater treatment. • A novel immobilization method was applied to horseradish peroxidase (HRP). • The HRP immobilized on hydrazine treated polyacrylonitrile fabrics activated with cyanuric chloride. • Immobilization process increased the reusability of HRP. • Immobilized HRP revealed higher activity in a broad range of pH's and high temperature. • The immobilized HRP proved to more efficient in removing phenol. [ABSTRACT FROM AUTHOR]

A novel plant peroxidase was isolated from the stem of Arabian balsam (Commiphora gileadensis) and purified using ammonium sulfate, followed by ion exchange chromatography (DEAE-Sepharose) and gel filtration (Sephcryl S-200). The newly isolated peroxidase was characterized as having a specific activity of 9503.3 unit/mg of protein after 20.3-fold purification, which yielded a recovery of 18.5%. Based on the subunit size, the purified peroxidase was a 40 kDa monomeric structure and presented high thermostability, as it was entirely stable at 55 °C for 30 min and retained approximately 13.6% of its activity at 85 °C. The optimal pH exhibited a broad value range (pH 7.0‐ 7.5). The kinetic parameters for the purified peroxidase were obtained. To increase the enzyme durability, efficiency and reusability, the peroxidase was entrapped onto a carboxymethyl cellulose/Fe 3 O 4 magnetic hybrid material. The immobilized enzyme was characterized by scanning electron microscopy (SEM) and FT-IR spectroscopy. It was tested at different pH values, storage times and temperatures, and its kinetic behavior was assessed. The immobilized enzyme maintained its activity upon storage at 4 and 25 °C for 8 weeks, and upon recycling for up to 15 uses. Arabian balsam peroxidase appears to be candidate for industrial applications. • The peroxidase was purified from arabian balsam stems. • The peroxidase was successfully entrapped onto a carboxymethylcellulose/Fe 3 O 4 magnetic hybrid material. • The immobilization method was improved the operational activity of peroxidase. • The immobilized enzyme was recyclable for 15 cycles. [ABSTRACT FROM AUTHOR]

This study was aimed to evaluate the relationship between growth hormone (GH) gene polymorphism and milk production in Najdi sheep. Two hundred Najdi ewes were used to determine the daily milk yield (DMY). The complete CDS of the Najdi sheep GH gene is1950 in length, GenBank acc. no. KU310891.1. Najdi sheep GH protein consists of 217 amino acids GenBank ALT22407.1 with conversion amino acid arginine number 121 to amino acid lysine (R121K). A novel five SNPs were detected in Najdi sheep GH gene (G871A, A1259C, G1383A, A1486G and A1509G). A significant association between the detected SNPs genotypes and daily milk yield was found in this study. The regression analysis indicated the positive effect of genotype and SNPs on DMY. Individuals carrying homozygote mutant alleles had the highest DMY. Consequently, these SNP may be useful indicators in the selection of ewes for milk production. [ABSTRACT FROM AUTHOR]

In the present study, nanodiamond (ND) was blended with polymethyl methacrylate (PMMA) and then electrospun into nanofibers (nfPMMA-ND) for the immobilization of horseradish peroxidase (HRP). The maximum immobilization efficiency of HRP (96%) was detected at 10% ND and pH 7.0. ATR-FTIR, SEM and TEM were used to characterize the immobilized enzyme. The immobilized enzyme retained 60% of its initial activity after ten reuses. The pH was shifted from 7.0 for soluble HRP to 7.5 for the immobilized enzyme. The soluble HRP had an optimum temperature of 30 °C, whereas this temperature was shifted to 40 °C for the immobilized enzyme. The substrate analogs were oxidized by immobilized HRP with higher efficiencies than those of soluble HRP. The kinetic results showed that the soluble HRP had more affinity toward guiacol and H2O2 than immobilized HRP. The effect of metal ions on soluble and immobilized HRP was studied. The immobilized HRP was markedly more stable when it exposed to urea, isopropanol, butanol and heptane compared with the soluble enzyme. The immobilized HRP exhibited high resistance to proteolysis by trypsin than that of soluble enzyme. In conclusion, the nfPMMA-ND-HRP could be employed in several applications such as biosensor, biomedical and bioremediation. [ABSTRACT FROM AUTHOR]

In this study, a new support has been developed by immobilization of α-amylase onto modified magnetic Fe3O4-nanoparticles. The characterization of soluble and immobilized α-amylases with regards to kinetic parameters, pH, thermal stability and reusability was studied. The effect of polypyrrole/silver nanocomposite (PPyAgNp) percentage on weight of Fe3O4 and pH on the immobilization of α-amylase was studied. The highest immobilization efficiency (75%) was detected at 10% PPyAgNp/Fe3O4-nanocomposite and pH 7.0. Immobilization of α-amylase on PPyAgNp/Fe3O4-nanocomposite was characterized by FT-IR spectroscopy and scanning electron microscopy. The reusability of the immobilized enzyme activity was 80% of its initial activity after 10 reuses. The immobilized enzyme was more stable towards pH, temperature and metal ions compared with soluble enzyme. The kinetic study appeared higher affinity of immobilized enzyme (Km 2.5 mg starch) compared with soluble enzyme (Km 3.5 mg starch). In conclusion, the immobilization of α-amylase on PPyAgNp/Fe3O4-nanocomposite could successfully be used in industrial and medical applications. [ABSTRACT FROM AUTHOR]

Objective: The evaluation of antioxidant activity of grape from different cultivars was conducted by several methods. Materials and Methods: Scavenging of 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical, scavenging of 2,2'-azino-bis (3-ethylbenzo-thiazoline-6-sulfonic acid) (ABTS) and formation of phosphate/molybdenum complex. Results: The phenolic content of peel and flesh from different cultivars of grapes showed concentration dependent scavenging of DPPH and ABTS radicals and formation of phosphate/ molybdenum complex. The results appeared high values of correlation coefficient (R²) between phenolic content of grapes and antioxidant activity indicating the strong correlation. The antioxidant assay IC50 value was variable among different grape cultivars. The activities of antioxidant enzymes were screened in the crude extracts of the peel and flesh of the grape cultivars tested, which had high, moderate and low levels of polyphenol oxidase, peroxidase and catalase, respectively. Conclusion: The results indicated that the imported grapes retained the most antioxidant activities. Finally, this study will be supply information on the antioxidant activity of grapes that benefits grapes producers, nutritionists and consumers. [ABSTRACT FROM AUTHOR]

Background: The miswak (Salvadora persica) is a natural toothbrush. It is well known that very little information has been reported on enzymes in miswak as medicinal plant. Recently, we study peroxidase in miswak. In the present study, the main goal of this work is to purify and characterize α-amylase from miswak. The second goal is to study the storage stability of α-amylase in toothpaste. Method: The purification method included chromatographaphy of miswak α-amylase on DEAE-Sepharose column and Sephacryl S-200 column. Molecular weight was determined by gel filtration and SDS-PAGE. Results: Five α-amylases A1, A4a, A4b, A5a and A5b from miswak were purified and they had molecular weights of 14, 74, 16, 30 and 20 kDa, respectively. α-Amylases had optimum pH from 6 to 8. Affinity of the substrates toward all enzymes was studied. Miswak α-amylases A1, A4a, A4b, A5a and A5b had Km values for starch and glycogen of 3.7, 3.7, 7.1, 0.52, 4.3 mg/ml and 5.95, 5.9 4.16, 6.3, 6.49 mg/ml, respectively. The optimum temperature for five enzymes ranged 40°C- 60°C. Miswak α-amylases were stable up to 40°C- 60°C after incubation for 30 min. Ca+2 activated all the miswak α-amylases, while Ni2+, Co+2 and Zn+2 activated or inhibited some of these enzymes. The metal chelators, EDTA, sodium citrate and sodium oxalate had inhibitory effects on miswak α-amylases. PMSF, p-HMB, DTNB and 1,10 phenanthroline caused inhibitory effect on α-amylases. The analysis of hydrolytic products after starch hydrolysis by miswak α-amylases on paper chromatography revealed that glucose, maltose, maltotriose and oligosaccharide were the major products. Crude miswak α-amylase in the toothpaste retained 55% of its original activity after 10 months of storage at room temperature. Conclusions: From these findings, α-amylases from miswak can be considered as beneficial enzymes for pharmaceuticals. Therefore, we study the storage stability of the crude α-amylase of miswak, which contained the five α-amylases, in toothpaste. The enzyme in the toothpaste retained 55% of its original activity after 10 months of storage at room temperature. [ABSTRACT FROM AUTHOR]

The strong catalytic performance, eco-friendly reaction systems, and selectivity of enzyme-based biocatalysts are extremely interesting. Immobilization has been shown to be a good way to improve enzyme stability and recyclability. Chitosan-incorporated metal oxides, among other support matrices, are an intriguing class of support matrices for the immobilization of various enzymes. Herein, the cross-linked chitosan/zinc oxide nanocomposite (CS/ZnO) was synthesized and further improved by adding iron oxide (Fe2O3) nanoparticles. The final cross-linked CS/ZnO/Fe2O3 nanocomposite was used as an immobilized support for catalase and is characterized by SEM, EDS, and FTIR. The nanocomposite CS/ZnO/Fe2O3 enhanced the biocompatibility and immobilized system properties. CS/ZnO/Fe2O3 achieved a higher immobilization yield (84.32%) than CS/ZnO (37%). After 10 repeated cycles, the remaining immobilized catalase activity of CS/ZnO and CS/ZnO/Fe2O3 was 14% and 45%, respectively. After 60 days of storage at 4 °C, the remaining activity of immobilized enzyme onto CS/ZnO and CS/ZnO/Fe2O3 was found to be 32% and 47% of its initial activity. The optimum temperature was noticed to be broad at 25–30 °C for the immobilized enzyme and 25 °C for the free enzyme. Compared with the free enzyme optimum pH (7.0), the optimum pH for the immobilized enzyme was 7.5. The Km and Vmax values for the free and immobilized enzyme on CS/ZnO, and the immobilized enzyme on CS/ZnO/Fe2O3, were found to be 91.28, 225.17, and 221.59 mM, and 10.45, 15.87, and 19.92 µmole ml−1, respectively. Catalase immobilization on CS/ZnO and CS/ZnO/Fe2O3 offers better stability than free catalase due to the enzyme's half-life. The half-life of immobilized catalase on CS/ZnO/Fe2O3 was between 31.5 and 693.2 min. [ABSTRACT FROM AUTHOR]

Horseradish peroxidase (HRP) enzyme was effectively encapsulated onto an Fe3O4 nanoparticle–polymethyl methacrylate (PMMA) film via the casting method. The HRP was immobilized on the 0.5% Fe3O4Np–PMMA film and characterized by Fourier transform infrared spectroscopy and field emission scanning electron microscopy. Moreover, the reusability, thermal stability, optimum pH, optimum temperature, the influence of metal ions, and the effects of detergent and organic solvent were investigated. After optimizing the immobilization conditions, the highest efficiency of the immobilized enzyme was 88.4% using 0.5% Fe3O4Np–PMMA. The reusability of the immobilized HRP activity was 78.5% of its initial activity after being repeatedly used for 10 cycles. When comparing the free and immobilized forms of the HRP enzyme, changes in the optimum temperature and optimum pH from 30 to 40 °C and 7.0 to 7.5, respectively, were observed. The Km and Vmax for the immobilized HRP were estimated to be 41 mM, 0.89 U/mL for guaiacol and 5.84 mM, 0.66 U/mL for H2O2, respectively. The high stability of the immobilized HRP enzyme was obtained using metal ions, a high urea concentration, isopropanol, and Triton X-100. In conclusion, the applicability of immobilized HRP involves the removal of phenol in the presence of hydrogen peroxide, therefore, it could be a potential catalyst for the removal of wastewater aromatic pollutants. [ABSTRACT FROM AUTHOR]

In this work, we propose a facile technique to dually-immobilize α-amylase and horseradish peroxidase (HRP) as two different enzyme models via entrapment within two distinct polymeric electrospun fibers by simple mixing steps and compare their properties with both individually immobilized forms and with the free counterparts. The immobilization was verified using Fourier transform infrared spectroscopy (FTIR) and Field emission scanning electron microscope (FESEM). The immobilization efficiencies for the dual-immobilized HRP and α-amylase were 89% and 85%, respectively. The retained catalytic activities of the dual-immobilized HRP and α-amylase enzymes were observed to be 79% and 80.2% after 10 cycles, respectively. After storage for 12 weeks, the dual-immobilized enzymes still retained nearly 90% activities similar to the individually immobilized ones. This immobilization procedure did not appear to exert either negative or back inhibitory effects upon both enzymes with respect to the different enzymatic assay procedures. This approach demonstrates that two or more type of enzymes could be mixed with different polymers individually and undergoes electrospinning simultaneously. We believe that this approach is expected to considerably promote and extend the application of multi-enzyme systems and worth further investigation for potential enzyme mediated cascade reactions. Unlabelled Image • Two distinct polymeric electrospun fibers were fabricated by dual immobilization of HRP and α-amylase. • The two immobilized enzymes had enhanced pH and storage stability. • The two immobilized enzymes had enhanced kinetics parameters. • The two immobilized enzymes retained 80% of the initial activity after 10 cycles. [ABSTRACT FROM AUTHOR]

Background: Iron magnetic nanoparticles have attracted much attention. They have been used in enzyme immobilization because of their properties such as product is easily separated from the medium by magnetic separation. The present work was designed to immobilize horseradish peroxidase on Fe3O4 magnetic nanopraticles without modification. Results: In the present study, horseradish peroxidase (HRP) was immobilized on non-modified Fe3O4 magnetic nanoparticles. The immobilized HRP was characterized by FT-IR spectroscopy, scanning electron microscopy, and energy dispersive X-ray. In addition, it retained 55% of its initial activity after 10 reuses. The optimal pH shifted from 7.0 for soluble HRP to 7.5 for the immobilized HRP, and the optimal temperature shifted from 40°C to 50°C. The immobilized HRP is more thermostable than soluble HRP. Various substrates were oxidized by the immobilized HRP with higher efficiencies than by soluble HRP. Km values of the soluble and immobilized HRP were 31 and 45 mM for guaiacol and 5.0 and 7.0 mM for H2O2, respectively. The effect of metals on soluble and immobilized HRP was studied. Moreover, the immobilized HRP was more stable against high concentrations of urea, Triton X-100, and isopropanol. Conclusions: Physical immobilization of HRP on iron magnetic nanoparticles improved the stability toward the denaturation induced by pH, heat, metal ions, urea, detergent, and water-miscible organic solvent. [ABSTRACT FROM AUTHOR]

Severe acute respiratory syndrome-coronavirus 2 (SARS-CoV-2), the responsible agent for the coronavirus disease 2019 (Covid-19), has its entry point through interaction with angiotensin converting enzyme 2 (ACE2) receptors, highly expressed in lung type II alveolar cells and other tissues, like heart, pancreas, brain, and vascular endothelium. This review aimed to elucidate the potential role of leukotrienes (LTs) in the pathogenesis and clinical presentation of SARS-CoV-2 infection, and to reveal the critical role of LT pathway receptor antagonists and inhibitors in Covid-19 management. A literature search was done in PubMed, Scopus, Web of Science and Google Scholar databases to find the potential role of montelukast and other LT inhibitors in the management of pulmonary and extra-pulmonary manifestations triggered by SARS-CoV-2. Data obtained so far underline that pulmonary and extra-pulmonary manifestations in Covid-19 are attributed to a direct effect of SARS-CoV-2 in expressed ACE2 receptors or indirectly through NF-κB dependent induction of a cytokine storm. Montelukast can ameliorate extra-pulmonary manifestations in Covid-19 either directly through blocking of Cys-LTRs in different organs or indirectly through inhibition of the NF-κB signaling pathway. [ABSTRACT FROM AUTHOR]