Optimal Ionic Strength Research Articles

Kinetic studies on optimized extracellular laccase from Trichoderma harzianum PP389612 and its capabilities for azo dye removal

BackgroundAzo dyes represent a common textile dye preferred for its high stability on fabrics in various harsh conditions. Although these dyes pose high-risk levels for all biological forms, fungal laccase is known as a green catalyst for its ability to oxidize numerous dyes.MethodsTrichoderma isolates were identified and tested for laccase production. Laccase production was optimized using Plackett–Burman Design. Laccase molecular weight and the kinetic properties of the enzyme, including Km and Vmax, pH, temperature, and ionic strength, were detected. Azo dye removal efficiency by laccase enzyme was detected for Congo red, methylene blue, and methyl orange.ResultsEight out of nine Trichoderma isolates were laccase producers. Laccase production efficiency was optimized by the superior strain T. harzianum PP389612, increasing production from 1.6 to 2.89 U/ml. In SDS-PAGE, purified laccases appear as a single protein band with a molecular weight of 41.00 kDa. Km and Vmax values were 146.12 μmol guaiacol and 3.82 μmol guaiacol/min. Its activity was stable in the pH range of 5–7, with an optimum temperature range of 40 to 50 °C, optimum ionic strength of 50 mM NaCl, and thermostability properties up to 90 °C. The decolorization efficiency of laccase was increased by increasing the time and reached its maximum after 72 h. The highest efficiency was achieved in Congo red decolorization, which reached 99% after 72 h, followed by methylene blue at 72%, while methyl orange decolorization efficiency was 68.5%.ConclusionTrichoderma laccase can be used as an effective natural bio-agent for dye removal because it is stable and removes colors very well.

Purification and characterization of glutamate dehydrogenase from rainbow trout (Oncorhynchus mykiss) liver and molecular docking studies.

Glutamate dehydrogenase (GDH) participates in the energy metabolism of proteins and the synthesis of metabolites important for the organism. In this study, GDH enzyme was purified from the liver of rainbow trout (Oncorhynchus mykiss) by 2',5'-ADP Sepharose 4B affinity chromatography in one step. As a result of this purification process, GDH enzyme was purified 171-fold with 5.83U/mg protein-specific activity. The characterization experiments presented that the storage stability of the purified GDH enzyme was determined as -80°C; optimum temperature 40°C; it was determined that the optimum ionic strength was 100mM phosphate buffer and the optimum pH was 8.00. Sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and PAGE studies showed that the natural molar mass of the purified GDH enzyme was 346.74kDa, and the molar mass of its subunits was 53.71kDa. Km and Vmax values for substrates and coenzymes of GDH enzyme purified from rainbow trout liver were calculated, and the lowest Km value was found in NAD+ (1.86mM) and the highest Vmax value in NH4 + (1.79U/mL). The effects of some metal ions, vitamins, and solvents on the activity of the purified GDH enzyme were investigated and also IC50 values and inhibition types. The metal ion with the lowest IC50 value is Ag+ (8.65 ± 1.68μM), and the vitamin is B6 (0.77 ± 0.04mM). The binding affinities of inhibitors were investigated with molecular docking, based on the conformational state of GDH.

Purification, characterization of glutathion reductase enzyme from sheep splen tissue and investıgatıon of the effects of some antibiotics on enzyme activity

In this study, glutathione reductase (EC 1.8.1.7; GR, Glutathione: NADP+ oxidoreductase), which is the key enzyme of antioxidant metabolism, was purified from sheep spleen using ammonium sulfate precipitation and 2', 5'-ADP Sepharose-4B affinity chromatography. As a result of purification, the GR enzyme was purified, with 20.03 EU/mg.protein of specific activity, 1564.8 times a yield of 40.61%. The purity of the enzyme was checked by SDS-PAGE. In the characterization studies, optimum pH, optimum ionic strength, stable pH, optimum temperature and subunit molecular mass of the enzyme were determined. In addition, KM and Vmax values were found to determine the enzyme's affinity for GSSG and NADPH substrates. It was determined as KM constant 0.0061 mM and Vmax value 0.259 EU/mL, for NADPH, KM constant was determined as 0.351 mM and Vmax value was determined as 0.604 EU/mL for GSSG. In addition, the effects of ampicillin, streptomycin sulfate, gentamicin, cefoperazone sodium and precort-lyo on enzyme activity were investigated. It was determined that these drugs showed an inhibitory effect on GR enzyme activity purified from sheep spleen tissue. The IC50 values for precort-lyo, ampicillin, streptomycin sulfate, cefoperazone sodium, and gentamicin were 1.27 mM, 3.22 mM, 7.95 mM, 16.97 mM, and 17.20 Mm, respectively; and Ki constants were calculated as 0.466±0.387 mM (competitive), 1.057±0.110 mM (non-competitive), 3.386±1.305 mM (competitive), 4.910±0.960 mM (competitive), and 20.770±8.169 mM (non-competitive), respectively.

Development of a new affinity chromatography method for purification of horseradish peroxidase enzyme.

In this study, benzohydroxamic acid molecules were synthesized from methyl 4-amino-2-methoxy, methyl 4-amino-3-nitro, methyl 4-amino-3-methyl, and methyl 4-amino-3-chloro benzoate molecules, and the horseradish peroxidase (HRP) enzyme was purified in one step using the affinity chromatography technique for the first time. The IC50 and Ki values for the 4-amino 3-methyl benzohydroxamic acid molecule were 0.136 and 0.132 ± 0.054μM, respectively, while the IC50 and Ki values for the 4-amino-3-nitro benzohydroxamic acid molecule were 56.00 and 51.90 ± 9.90μM, respectively. It was found that the IC50 and Ki values for the 4-amino-3-chloro benzohydroxamic acid molecule were 218.33 and 175.67 ± 43.78μM, respectively, whereas the IC50 and Ki values for the 4-amino-2-methoxy benzohydroxamic acid molecule were 306.00 and 218.00 ± 68.80μM, respectively. The HRP enzyme was synthesized from 4-amino-2-methoxy hydroxamic acid column with a 35.97% yield 601.13 times, 4-amino-3-nitro hydroxamic acid column, with a 14.00% yield 404.11 times, 4-amino-3-methyl hydroxamic acid column with an 8.70% yield 394.88 times, and 4-amino-3-chloro hydroxamic acid column with a 4.48% yield 284.85 times. Thus, the HRP enzyme was purified in a single step with hydroxamic acids, and its molecular weight was found to be 44kDa. The optimum pH was 8.0, the optimum temperature was 15°C, and the optimum ionic strength was 0.4M for the purified HRP enzyme.

An in-depth investigation of the impact of salt nature on the formulation of microemulsion systems

Electrolytes have a wide range of technological applications. Despite the recent improvements in characterizing and predicting the phase behavior of microemulsion systems by hydrophilic-lipophilic deviation (HLD) and net-average curvature (NAC) frameworks, they are ineffective in the presence of different salts. This work seeks to bridge this gap by investigating the influence of salt nature on the microemulsion phase formulation. First, a one-dimensional salinity scan on different microemulsion systems consisting of sodium dodecyl benzene sulfonate as a surfactant, hexane as an oil and, several brines was carried out, and the effect of each salt on the phase behavior were precisely evaluated. The results for optimum salinity and solubilization parameter of different salts were consistent with the Hofmeister series. In addition, multiple linear regression model is presented to accurately predicting the optimum salinity of different salts using this research data and all the available experimental data. The results revealed that the values estimated by this model is in significant consistency with the experimental data by correlation coefficient of 0.92. Finally, the effect of salt type on the NAC parameters (length parameter, and characteristic length) were evaluated to improve the predicting ability of this equation of state in the presence of various salts. We found that salt nature has a significant impact on both these parameters. It was found that the length parameter is linearly dependent on the optimum ionic strength of salts while the salting-out capacity of each salt was predominant factor affecting the characteristic length.

Preparation of biochar-based surface molecularly imprinted polymers and evaluation of their selective adsorption and removal of carbaryl from rice and corn

The residue of carbaryl in food is a threat to human health. In this study, activated soybean shell biochar (A-SBC) was used as a carrier, methacrylic acid (MAA) was used as a functional monomer, and carbaryl was used as a template molecule to synthesize the activated biochar surface molecularly imprinted polymer (A-SBC@MIP). The synthesized A-SBC@MIP was characterized by SEM, FT-IR, XRD and XPS techniques, and then applied as adsorbent for carbaryl removal. The adsorption capacity of A-SBC@MIP for carbaryl was 8.6 mg‧g−1 and the imprinting factor was 1.49 at the optimum ionic strength and pH. The kinetic and isothermal data indicated that it had fast mass transfer rate and high binding capacity(Qmax=47.9 mg‧g−1). A-SBC@MIP showed good regenerative properties and the adsorption of carbaryl was excellent in its structural analogues. A solid-phase extraction (SPE) column composed of A-SBC@MIP was developed for the detection of rice and corn under optimized conditions, with recoveries of 93–101% for the spiked carbaryl. The limit of detection (LOD) of the method was 3.6 μg‧kg−1 with good linearity (R2=0.994) in the range of 0.01–5.00 mg‧L−1. The results show that the developed MIPs-SPE can enrich carbaryl from food samples as a specific and cost-effective method.

Characterization of Guaiacol Peroxidase Enzyme from Carambola Fruit

Carambola is a fruit grown in tropical and subtropical regions of the world. Natural antioxidants including vitamin C, carotenoids, and certain phenolic substances are abundant in carambola fruit. As antioxidants support health by acting as nutraceutical and functional food additives, they help preserve food by preventing oxidation processes. The oxidation of various organic or inorganic substrates by hydrogen peroxide or organic peroxides as terminal oxidants is a process in which peroxidase, which is abundantly present in fruits and vegetables, participates. In this study, guaiacol peroxidase enzyme from carambola fruit was partially purified and characterized. Purification procedure made up the homogenate preparation, ammonium sulfate precipitation, and dialysis. After purification, optimum ionic strength, pH and substrate concentration were investigated. These values were determined as 200 mM Tris, pH: 7.5, 7.5 mM H2O2 and 15 mM guaiacol for carambola fruit guaiacol peroxidase enzyme, respectively.

Purification and Characterization of Glutathione Reductase Enzyme from Arum Maculatum Leaf

Arum species grow in temperate and Mediterranean climates and have been used for hundreds of years for food and medicinal purposes, although they are highly toxic if not cooked using proper techniques. Glutathione reductase (GR) is a member of the pyridine nucleotide disulfide oxidoreductase family of flavoenzymes that catalyzes the reduction of glutathione disulfide (GSSG) to reduced GSH using NADPH or NADH. In this study, GR enzyme was characterized by partial purification processes including homogenate preparation, ammonium sulfate precipitation and dialysis from the leaf of Arum maculatum plant. The highest enzyme activity was found at 40-60% saturation range. Optimum ionic strength, pH and substrate concentration were investigated for GR enzyme from A. maculatum leaf. As a result of the study, these values were found to be 150 mM potassium phosphate buffer, pH 7.00, and 0.18 mM, respectively. The GR enzyme was partially purified from the leaf of the A. maculatum with a specific activity of 1.640 EU mg-1 in 34.9% yield, 1.108-fold. This study is the first study in terms of purification and characterization of GR enzyme from A. maculatum leaf.

Glutatyon S-Transferaz Enziminin Tavuk Karaciğerinden Saflaştırılması ve Karakterizasyonu

In this study, the glutathione S-transferase enzyme (GST; EC 2.5.1.18) was purified with 8.35 EU/mL specific activity, 24.56 times 8% yield, from chicken liver, using ammonium sulfate precipitation and glutathione-agarose affinity chromatography. In order to control the purity of the enzyme, SDS-PAGE was performed and a single band was obtained. The molecular mass of the subunit was calculated as approximately 30.9 kDa. In addition, the optimum pH value of the enzyme (8.5 in Tris-HCl); optimum ionic strength (150 mM with Tris-HCl); optimum temperature (70 oC); stable pH value (8.5 with Tris-HCl) was determined. The KM value for the GSH substrate of the enzyme was 0.802 mM, the Vmax value was 1.833 EU/mL; For CDNB, the KM value was calculated as 3.6 mM and the Vmax value was calculated as 2.829 EU/mL.

Characterization of Catalase Enzyme from Leaf Tissue of Aronia (Aronia melanocarpa) Plant

Aronia is among the most antioxidant containing plants which is found commonly around the world. Aronia cultivation started in Turkey for the first time in 2012 at the Atatürk Central Research Institute of Garden Cultures, and a plantation was constructed in the experimental area. Since antioxidants help to preserve food by blocking oxidation processes and contributing to the health promotion provided by numerous dietary supplements, nutraceutical and functional food additives, antioxidant capacity of these plants should be well characterized. To assess and evaluate the antioxidant content of foods and plant products, many approaches are utilized. In this study, catalase (CAT) enzyme was partially purified from aronia plant leaf tissue and characterization was carried out. Purification process consisted of homogenate preparation, ammonium sulfate precipitation and dialysis. The optimal ionic strength, pH, substrate concentration and enzyme quantity were examined. These values were found to be 300 mM Tris, pH:8.0, 12 mM H2O2 and 75 μl, respectively, for the catalase enzyme of the Aronia plant leaf tissue. This study is the first in the literature dealing with the characterization of antioxidant enzyme from Aronia plant.

Development of Monoclonal Antibody-Based EIA for Tetranor-PGDM which Reflects PGD2 Production in the Body.

Tetranor-PGDM is a metabolite of PGD2. Urinary tetranor-PGDM levels were reported to be increased in some diseases, including food allergy, Duchenne muscular dystrophy, and aspirin-intolerant asthma. In this study, we developed a monoclonal antibody (MAb) and a competitive enzyme immunoassay (EIA) for measuring tetranor-PGDM. Spleen cells isolated from mice immunized with tetranor-PGDM were utilized to generate Ab-producing hybridomas. We chose hybridomas and purified MAb against tetranor-PGDM to develop competitive EIA. The assay evaluated the optimal ionic strength, pH, precision, and reliability. Specificity was determined by cross-reactivity to tetranor-PGEM, tetranor-PGFM, and tetranor-PGAM. Recovery was determined by spiking experiments on artificial urine. Optimal ionic strength was 150 mM NaCl, and optimal pH was pH 7.5. Metabolites other than tetranor-PGDM did not show any significant cross-reactivity in the EIA. The assay exhibited a half-maximal inhibition concentration (IC50) of 1.79 ng/mL, limit of detection (LOD) of 0.0498 ng/mL, and range of quantitation (ROQ) value of 0.252 to 20.2 ng/mL. The intra- and inter-assay variation for tetranor-PGDM was 3.9–6.0% and 5.7–10.4%, respectively. The linearity-dilution effect showed excellent linearity under dilution when artificial urine samples were applied to solid-phase extraction (SPE). After SPE, recovery of tetranor-PGDM in artificial urine averaged from 82.3% to 113.5% and was within acceptable limits (80%–120%). We successfully generated one monoclonal antibody and developed a sensitive competitive EIA. The established EIA would be useful for routine detection and monitoring of tetranor-PGDM in research or diagnostic body fluids.

Characterization of glutathione S ‐transferase enzyme from brown meagre ( Sciaena umbra ) and inhibitory effects of heavy metals

Glutathione S-transferase (GST) detoxifies a broad spectrum of xenobiotics, especially in chemotherapeutic drugs, endogenous molecules, and environmental pollutants. Since the enzyme metabolizes toxic compounds, it has been extensively studied in many living things including aquatic organisms. In the current study, the GST enzyme was purified from brown meagre (Sciaena umbra) muscle tissue for the first time. Then, kinetic parameters of the enzyme were determined as optimum ionic strength: 20 mM Tris/HCl, optimum pH: 7.0 (Tris/HCl), and optimum substrate concentration: 3.125 mM. Eventually, inhibitory effects of the heavy metals were evaluated. IC50 values of the tested metal ions were calculated to be 0.1112, 0.6113, 0.727, and 0.7774 mM for Cd2+ , Fe3+ , Ag+ , and Cu2+ , respectively. Our results show that these heavy metals inhibit GST at very low concentrations which could cause dangerous results for aquatic systems.

Characterization of Recombinant Endonuclease IV from Mycobacterium tuberculosis

Mycobacterium tuberculosis cells contain two apurinic/apyrimidinic (AP) endonucleases, endonuclease IV (MtbEnd) and exonuclease III (MtbXthA), the former playing a dominant role in protecting mycobacterial DNA from oxidative stress. Mycobacterial endonuclease IV substantially differs from its homologs found in Escherichia coli and other proteobacteria in a number of conserved positions important for DNA binding and AP site recognition. The M. tuberculosis end gene was cloned, and recombinant MtbEnd purified and characterized. The protein efficiently hydrolyzed DNA at the natural AP site and its 1'-deoxy analog in the presence of divalent cations, of which Ca^(2+), Mn^(2+), and Co^(2+) supported the highest activity. Exonuclease activity was not detected in MtbEnt preparations. The pH optimum was estimated at 7.0-8.0; the ionic strength optimum, at ~50 mM NaCl. Enzymatic activity of MtbEnd was suppressed in the presence of methoxyamine, a chemotherapeutic agent that modifies AP sites. Based on the results, MtbEnd was assumed to provide a possible target for new anti-tuberculosis drugs.

Glutathione S-transferase: Purification and Characterization from Quail (Coturnix coturnix japonica) Liver and the Impact of Some Metal Ions on Enzyme Activity

The objective of this study was to examine the inhibitory effect of some heavy metals on the glutathione S-transferase (GST) enzyme, which is one of the major enzymes of glutathione metabolism purified from quail liver tissues. The quail liver GST enzyme was purified with 15.86 EU/mg specific activity, in a yield of 12.36% and 46.1 purification fold by ammonium sulfate precipitation and glutathione-agarose affinity chromatography. The molecular weight of subunits of the enzyme and the purity were determined by SDS-PAGE. In the characterization studies, the optimum pH of the GST enzyme was determined to be pH = 8.0 in Tris/HCl buffer. Optimum ionic strength was determined to be 140 mM in Tris/HCI buffer. Stable pH was found to be pH = 8.5 in Tris/HCl buffer. Optimum temperature was found to be 50 °C. KM and Vmax values for substrates 1-chloro-2,4-dinitrobenzene (CDNB) and GSH of the enzyme were determined to be KM 0.048 mM Vmax 0.479 EU/mL and KM 0.114 mM Vmax 0.672 EU/mL, respectively. In vitro inhibition effects of metal ions, including Ag+, Ni2+, Cd2+, Fe2+, Pb2+, Co2+ Zn2+, and Al3+, were investigated on the GST enzyme activity. The results showed that Ag+, Cd2+, Ni2+ Zn2+, and Al3+ metal ions inhibited GST enzyme (IC50 values 0.239, 0.250, 0.265, 0.320, 0.594 mM, respectively), while Fe2+, Pb2+, and Co2+ metal ions activated the enzyme. Finally, Ki values and inhibition types for these substances were determined by Lineweaver-Burk graphs.

Purification and Characterization of 6-Phosphogluconate Dehydrogenase from Japanese Quail (Coturnix, coturnix japonica) Erythrocytes

In this study, the 6PGD enzyme from Japanese quail erythrocytes was purified with specific activity of 52.84 EU/mg and 69% yield of purification by 2ˈ, 5ˈ- ADP Sepharose 4B affinity gel in a single chromatographic method. The purification folds of the enzyme were 4984 folds. The purified enzyme was checked using SDS polyacrylamide gel electrophoresis (SDS-PAGE) method; the result of gel showed a single band. The subunit molecular weight of the enzyme was calculated as 81 kDa by the SDS-PAGE method. The characterization studies of the 6PGD enzyme from erythrocytes of Japanese quail showed: the optimum ionic strength to be at 0.5 M Tris-HCl, optimum and stable pH values to be at 0.5 M Tris-HCl buffers pH 8.0. The optimal temperature for the enzyme activity was found at 60 ˚C. Finally, the KM and Vmax values for the 6PGD enzyme from Japanese quail’s erythrocytes were calculated respectively for the 6PGA the KM value found as 0.120 mM, Vmax value as 0.191 EU/mL and for NADP+ the KM value as 0.017 mM and Vmax value as 0.228 EU/mL.

Purification and characterization glutathione S-transferase enzyme from quail (Coturnix, coturnix japonica) heart and investigation the effect of some metal ions on enzyme activity

In this study glutathione S-transferase enzyme (EC: 2.5.1.18) from the heart of japonica quail was purified with 34.0 EU/mg specific activity, 10.44% purification yield and 78.29 purification folds and characterized. Purification processes are consist of three steps, firstly homogenate was prepared, and then ammonium sulfate precipitation was performed and finally glutathione-agarose gel affinity column chromatography was performed. To check the purity of GST enzyme used SDS-PAGE method. Then the M.W calculated at approximately 26.3 kDa by SDS-PAGE method. Enzymatic activity was determined spectrofotometrically according to Beutler`s method at 340 nm. Also characterizations study carry out, and the results obtained are stability-pH = 9.0 in Tris/HCL buffer, optimum pH = 8.0 in Tris/HCl buffer, optimum temperature 60 °C, optimum ionic strength was 1.2 M in Tris/HCl buffer. And kinetic studies performed for GST enzyme purified from quail heart by used both glutathione and 1-chloro 2,4-dinitrobenzen as substrate. KM and Vmax values are determined as 1.642 mM and 0.502 EU/mL respectively for GSH substrate and 3.880 mM and 0.588 EU/mL respectively for CDNB substrate. In addition, the effect of some metal ions (Cu2+, Cd2+, Fe2+, Fe3+ Zn2+, Ag+, Co2+, and Ti1+) were investigated on the GST enzyme activity in vitro.

SORPTION OF CERIUM(III) IONS ONTO CHELATING POLYMERIC SORBENT

In a present paper methods of concentration of Ce(III) from aqueous solutions onto synthetic polymer adsorbent. The sorption-photometric determination of the microquantities of cerium ions by new polymeric chelating sorbent, modified with dithizone has been studied. Sorption process was carried out under static conditions. Optimal characteristics of the sorption process: influence of pH, time of contact, effect of the initial concentration of metal, influence of ionic strength were studied. pH for extracting Ce is 5; the residence time is 210 min. Optimal ionic strength was achieved at a value of μ =0.6. The sorption capacity of the sorbent and the percentage recovery were determined from the difference in the initial and final concentrations of cerium(III) in the solution. The sorbability of cerium(III) ions was 91.38%, sorption capacity of sorbent with respect to cerium ions is 682.85 mg∙g-1. At the final stage, a desorption process was carried out using different (organic and mineral) acids with the same concentrations (0.5, 1.0, 1.5, and 2.0 M). 1M HCl has the highest eluting ability with respect to cerium (III) ions. Sorbent modified with dithizone based on a styrene-maleic anhydride (SMA) copolymer is proposed as synthetic sorbent with the best analytical properties (high sorption capacity, residence time 3 h with respect to cerium ions). Multiple use of the regenerated sorbent for concentration is possible. The developed techniques can be used to determine Ce(III) in standard samples, soil and tap water.

Compositional and Temperature Effects on the Rheological Properties of Polyelectrolyte-Surfactant Hydrogels.

The rheological properties of hydrogels prepared by physical interactions between oppositely charged polyelectrolyte and surfactant in micellar form were studied. Specifically, hyaluronan was employed as a negatively charged polyelectrolyte and Septonex (carbethopendecinium bromide) as a cationic surfactant. Amino-modified dextran was used as a positively charged polyelectrolyte interacting with sodium dodecylsulphate as an anionic surfactant. The effects of the preparation method, surfactant concentration, ionic strength (the concentration of NaCl background electrolyte), pH (buffers), multivalent cations, and elevated temperature on the properties were investigated. The formation of gels required an optimum ionic strength (set by the NaCl solution), ranging from 0.15–0.3 M regardless of the type of hydrogel system and surfactant concentration. The other compositional effects and the effect of temperature were dependent on the polyelectrolyte type or its molecular weight. General differences between the behaviour of hyaluronan-based and cationized dextran-based materials were attributed to differences in the chain conformations of the two biopolymers and in the accessibility of their charged groups.

Glutathione S-Transferase: Purification and Characterization of from Cherry Laurel (Prunus laurocerasus L.) and the Investigation In Vitro Effects of Some Metal Ions and Organic Compounds on Enzyme Activity

In this study, the cherry laurel flesh fruit was purified to obtain glutathione S-transferase, a well-known antioxidant enzyme. Enzyme purification was performed using two separate processes: gel filtration and affinity chromatography. The sodium dodecyl sulfate electrophoresis method was used for determining enzyme purity. The optimum pH, optimum temperature, optimum ionic strength, stable pH, and KM and Vmax values for glutathione and 1-chloro-2,4-dinitrobenzene were obtained for the enzyme as follows: 7.0 in the K-phosphate buffer, 30 °C, 0.125 M, 6.5 in the K-phosphate buffer, 0.344 mM, 0.89 mM, and 0.098 EU/ml, 0.214 EU/ml. Lineweaver-Burk graphs were used to examine the in vitro enzyme activity in order to determine the inhibitory effects of some metal ions such as Cd2+, Ni2+, Cu2+, and Mg2+ and organic compounds such as sodium dodecyl sulfate (SDS), ascorbic acid (vitamin C), benzoic acid, and ethylenediaminetetraacetic acid (EDTA). The IC50 and Ki values for each of the metal ions and organic molecules were calculated. According to the results, Ca2+ metal ion and sodium dodecyl sulfate compounds were found to be the best inhibitor with a Ki value of 0.06 ± 0.04 and 0.20 ± 0.27, respectively.

Linker-Mediated Assembly of Virus-Like Particles into Ordered Arrays via Electrostatic Control.

Nanoscale virus-like particles (VLPs), which are self-assembled from protein subunits, offer the possibility of generating hierarchically assembled functional materials such as biomimetic catalytic systems and optical metamaterials. We explore the capacity to control and tune a higher-order assembly of VLPs into ordered array materials over a wide range of ionic conditions using a combination of experimental and computational methods. The integrated methodology demonstrates that P22 VLP variants, genetically engineered to exhibit different surface charges, self-assemble into ordered arrays in the presence of PAMAM dendrimers acting as oppositely charged, macromolecular linkers. Ordered assembly occurs at an optimal ionic strength that strongly correlates with the VLP surface charge. The ordered VLP arrays exhibit the same long-range order and a similar configuration of VLP-bound dendrimers, regardless of the VLP surface charge. The experimentally validated model identifies key electrostatic and kinetic mechanisms underlying the self-assembly process and guides the modulation of dendrimer concentration as a control parameter to tune the assembly of VLPs. The integrated approach opens new design and control strategies to fabricate active functional materials via the self-assembly of engineered VLPs.