RESUMO
Vanillin is a commonly used synthetic flavoring agent in daily life. However, excessive intake of vanillin may pose risks to human health. Therefore, there is an urgent need for rapid and sensitive detection methods for vanillin. In this study, we developed a fluorescent sensor based on Cd-MOF for the sensitive and selective recognition of vanillin. The presence of vanillin leads to significant fluorescence quenching of Cd-MOF due to competitive absorption and photoinduced electron transfer (PET). The limit of detection was determined to be 39.6 nM, which is the lowest-among the reported fluorescent probes. The sensor was successfully applied for the detection of vanillin in real samples such as powdered milk and milk, with a recovery rate ranging from 96.88 % to 104.83 %. Furthermore, by immobilizing the Cd-MOF probe into a polyvinyl alcohol (PVA) film, we achieved a portable and visual detection composite materials for vanillin.
Assuntos
Benzaldeídos , Estruturas Metalorgânicas , Leite , Espectrometria de Fluorescência , Benzaldeídos/análise , Benzaldeídos/química , Leite/química , Animais , Espectrometria de Fluorescência/métodos , Estruturas Metalorgânicas/química , Pós , Corantes Fluorescentes/química , Limite de Detecção , Cádmio/análiseRESUMO
Vacuolar-type H+-ATPases (V-ATPases) play a crucial role in the life cycle of agricultural pests and represent a promising target for the development of novel insecticides. In this study, S18, a derivative of vanillin acquired from Specs database using a structure-based virtual screening methodology, was first identified as a V-ATPase inhibitor. It binds to subunit A of the enzyme with a Kd of 1 nM and exhibits insecticidal activity against M. separata. Subsequently, using S18 as the lead compound, a new series of vanillin derivatives were rationally designed and efficiently synthesized. and their biological activities were assessed. Among them, compound 3b-03 showed the strongest insecticidal activity against M. separata by effectively targeting the V-ATPase subunit A with Kd of 0.803 µM. Isothermal titration calorimetric measurements and docking results provided insights into its interaction with subunit A of V-ATPase, which could facilitate future research aimed at the development of novel chemical insecticides.
Assuntos
Benzaldeídos , Inseticidas , Simulação de Acoplamento Molecular , ATPases Vacuolares Próton-Translocadoras , Inseticidas/química , Inseticidas/farmacologia , Inseticidas/síntese química , Animais , Benzaldeídos/química , Benzaldeídos/farmacologia , Relação Estrutura-Atividade , ATPases Vacuolares Próton-Translocadoras/antagonistas & inibidores , ATPases Vacuolares Próton-Translocadoras/química , ATPases Vacuolares Próton-Translocadoras/metabolismo , Proteínas de Insetos/química , Proteínas de Insetos/antagonistas & inibidores , Proteínas de Insetos/metabolismo , Inibidores Enzimáticos/química , Inibidores Enzimáticos/farmacologia , Inibidores Enzimáticos/síntese química , Estrutura Molecular , HalogenaçãoRESUMO
Vanillin loaded-physically crosslinked hydrogel membranes made of PVA/chitosan/itaconic acid (PVA-CS-IA) were prepared using freezing-thawing (F-T) cycle method. To ensure the entanglement of PVA-CS-IA chains, three F-T cycles were repeated. The polymeric chains entanglements were confirmed and characterized by different instrumental characterizations. Physicochemical properties for example, swelling ratio, mechanical characteristics, gel fraction percentage (GF%), hydrolytic degradation, and thermal stability of PVA-CS-IA membrane were discussed in detail. The findings showed that the swelling ratio, mechanical characteristics, and hydrolytic degradation of the crosslinked membranes enhanced with increasing CS-IA contents in membranes composition; however, GF% gradually declined with CS-IA content. Additionally, cell viability test using HFB-4 cell line and antimicrobial activity against Staphylococcus aureus and Escherichia coli were evaluated using MTT assay and the bacterium growth inhibition percentage method; respectively. Notably, with varying incubation durations and membrane concentrations, all examined constructed hydrogels showed significant cell survival percentages. The findings supported the notion that produced hydrogel membranes might be used in a professional setting as antibacterial dressings or biomaterials for quick wound healing rate.
Assuntos
Antibacterianos , Benzaldeídos , Quitosana , Escherichia coli , Álcool de Polivinil , Staphylococcus aureus , Cicatrização , Quitosana/química , Quitosana/farmacologia , Álcool de Polivinil/química , Cicatrização/efeitos dos fármacos , Humanos , Staphylococcus aureus/efeitos dos fármacos , Escherichia coli/efeitos dos fármacos , Escherichia coli/crescimento & desenvolvimento , Benzaldeídos/química , Benzaldeídos/farmacologia , Antibacterianos/química , Antibacterianos/farmacologia , Linhagem Celular , Membranas Artificiais , Hidrogéis/química , Hidrogéis/farmacologia , Sobrevivência Celular/efeitos dos fármacos , SuccinatosRESUMO
In this work, chitosan was combined with bio-vanillin (BV) and kaolin clay (KC) to create a novel antifungal and biodegradable food packaging film. The chitosan/KC/BV film exhibited an antioxidant capacity of 80 % as measured by DPPH assay, which was significantly higher than that of the chitosan film which has 55.6 %). The film also demonstrated strong antimicrobial activity with a reduction of 90 % in the growth of E. coli and S. aureus compared to the control. Additionally, the chitosan/KC/BV film showed a 75 % reduction in fungal growth compared to chitosan film. Furthermore, the water vapor permeability of the chitosan film was reduced as 5.38 with the addition of KC/BV. The degradation study revealed that the chitosan/KC film degraded by 88 % within 20 days under composting conditions. Additionally, fresh-cut apple slices were used to examine the effectiveness of chitosan/KC/BV film as a packaging material. The fruit's weight loss and browning index showed satisfactory food preservation. Our research suggests that the chitosan/KC/BV film has great potential for use in the food sector due to its strong antioxidant, antimicrobial, and biodegradable properties.
Assuntos
Antibacterianos , Antifúngicos , Antioxidantes , Benzaldeídos , Quitosana , Embalagem de Alimentos , Caulim , Quitosana/química , Quitosana/farmacologia , Antibacterianos/química , Antibacterianos/farmacologia , Antioxidantes/química , Antioxidantes/farmacologia , Antifúngicos/química , Antifúngicos/farmacologia , Embalagem de Alimentos/métodos , Benzaldeídos/química , Benzaldeídos/farmacologia , Caulim/química , Caulim/farmacologia , Argila/química , Plásticos Biodegradáveis/química , Plásticos Biodegradáveis/farmacologia , Solubilidade , Espectroscopia de Infravermelho com Transformada de Fourier , Difração de Raios X , Escherichia coli , Staphylococcus aureusRESUMO
Surface-enhanced Raman scattering (SERS) offers a promising, cost-effective alternative for the rapid, sensitive, and quantitative analysis of potential biomarkers in exhaled gases, which is crucial for early disease diagnosis. However, a major challenge in SERS is the effective detection of gaseous analytes, primarily due to difficulties in enriching and capturing them within the substrate's "hotspot" regions. This study introduces an advanced gas sensor combining mesoporous gold (MesoAu) and metal-organic frameworks (MOFs), exhibiting high sensitivity and rapid detection capabilities. The MesoAu provides abundant active sites and interconnected mesopores, facilitating the diffusion of analytes for detection. A ZIF-8 shell enveloping MesoAu further enriches target molecules, significantly enhancing sensitivity. A proof-of-concept experiment demonstrated a detection limit of 0.32 ppb for gaseous benzaldehyde, indicating promising prospects for the rapid diagnosis of early stage lung cancer. This research also pioneers a novel approach for constructing hierarchical plasmonic nanostructures with immense potential in gas sensing.
Assuntos
Testes Respiratórios , Gases , Ouro , Estruturas Metalorgânicas , Análise Espectral Raman , Estruturas Metalorgânicas/química , Testes Respiratórios/métodos , Ouro/química , Gases/análise , Gases/química , Humanos , Análise Espectral Raman/métodos , Porosidade , Nanoestruturas/química , Benzaldeídos/química , Limite de Detecção , Nanopartículas Metálicas/químicaRESUMO
Polylactic acid (PLA) is widely known for its biocompatibility, biodegradability, and high transparency. However, it still has varied limitations such as flammability, UV sensitivity, and poor oxygen barrier properties. To address these issues, a bio-based compound, hexasubstituted cyclotriphosphazene (HVP), was synthesized by using vanillin and hexachlorocyclotriphosphazene to enhance the overall performance of PLA. The resulting PLA/HVP composites demonstrated improved mechanical strength and UV resistance. Specifically, PLA/3HVP, with a 3 wt% HVP loading, achieved a UL-94 V-0 rating and a high limiting oxygen index of 26.5 %. Cone calorimeter tests revealed that PLA/3HVP possessed a significantly longer ignition time and a lower peak heat release rate compared to pure PLA. These burning testing results indicated the enhanced fire resistance. Additionally, the oxygen transmission rate of PLA/3HVP was reduced by 81.1 % compared to pure PLA. When used as food packaging, the weight loss of mangoes covered with PLA/3HVP film was 2.2 % after 7 days, compared to 2.5 % with pure PLA film, highlighting its potential for food preservation applications.
Assuntos
Benzaldeídos , Retardadores de Chama , Embalagem de Alimentos , Oxigênio , Poliésteres , Raios Ultravioleta , Poliésteres/química , Embalagem de Alimentos/métodos , Benzaldeídos/química , Oxigênio/químicaRESUMO
Thermosetting resins are widely used in high-tech applications for excellent mechanical robustness and chemical resistance. With increasing attention to the environmental and usage safety issues, it is necessary to develop bio-derived, recyclable, tough, and fire-retardant thermosetting resins. Herein, a high-performance, vanillin-based vitrimer (CIP1.0) was prepared. The CIP1.0 with 1.0 wt% phosphorus passes vertical burning (UL-94) V-0 rating with a limiting oxygen index (LOI) of 27.2%. The phosphorus-containing and Schiff base groups act synergistically in gas and condensed phases during combustion, endowing CIP1.0 with outstanding fire retardancy. The CIP1.0 shows excellent toughness with high elongation at break of 45.0% due to the π-π stacking of numerous rigid aromatic groups and appropriate cross-linking density. The highly symmetrical structure and low polarizability of CIP1.0 result in a low dielectric constant. The CIP1.0 exhibits superior antimicrobial properties. The CIP1.0 can be reprocessed by hot-pressing at 140 °C for 10 min. The non-destructive, closed-loop recycling of carbon fibers in the carbon fiber-reinforced CIP1.0 composite can be achieved under mild conditions due to the degradable Schiff base groups of CIP1.0. In this work, a bio-derived, tough, fire-retardant, low dielectric, and antimicrobial vitrimer is prepared to provide a rational strategy for the design of advanced environmentally friendly thermosetting resins.
Assuntos
Antibacterianos , Benzaldeídos , Retardadores de Chama , Bases de Schiff , Bases de Schiff/química , Antibacterianos/química , Antibacterianos/farmacologia , Benzaldeídos/química , Benzaldeídos/farmacologia , ReciclagemRESUMO
Generally, oligolysine has poor antibacterial effect and almost no antibacterial activity. Herein, low cost and easily available oligolysines were chosen to prepare injectable antibacterial hydrogel (PVAL-gel) for wound healing. The hydrogel network was formed by cross-linking vanillin acrylate-N, N-dimethylacrylamide copolymer P(VA-co-DMA), oligolysine and adipate dihydrazide through Schiff base bond. The obtained hydrogel PVAL-gel exhibited not only excellent self-healing capability and injectability, but also the efficient contact antibacterial ability and good inhibitory effects on E.coli and S.aureus. In vitro, 99.9 % of pathogenic bacteria was killed within 160 min. Furthermore, the injectable PVAL-gel could rapidly eradicate bacteria in infected wounds and notably enhance the healing of full-thickness skin wounds. Therefore, PVAL-gel is expected to be used as a high-end dressing for the treatment of infected skin wounds, which can promote wound healing.
Assuntos
Antibacterianos , Escherichia coli , Hidrogéis , Staphylococcus aureus , Cicatrização , Cicatrização/efeitos dos fármacos , Hidrogéis/química , Hidrogéis/farmacologia , Hidrogéis/administração & dosagem , Antibacterianos/farmacologia , Antibacterianos/química , Antibacterianos/administração & dosagem , Escherichia coli/efeitos dos fármacos , Animais , Staphylococcus aureus/efeitos dos fármacos , Benzaldeídos/química , Benzaldeídos/farmacologia , Benzaldeídos/administração & dosagem , Testes de Sensibilidade Microbiana , Injeções , Adipatos/química , Adipatos/farmacologia , Camundongos , Acrilamidas/química , Acrilamidas/farmacologia , Polilisina/química , Polilisina/farmacologiaRESUMO
The revised structure, 2, assigned to the title natural product has been prepared by chemical synthesis using a reaction sequence involving six simple steps starting from 2,3-dimethoxybenzaldehyde and proceeding via intermediates 8, 12, and 14. A comparison of the NMR data acquired on synthetically derived compound 2 with those reported for the natural product reveals an excellent match. Preliminary biological screening of compound 2 along with analogues/precursors 7, 9, 10, 11, 13, 14, and 15 revealed that none exhibited antibacterial, antifungal or cytotoxic effects.
Assuntos
Alcaloides , Estrutura Molecular , Alcaloides/química , Alcaloides/farmacologia , Alcaloides/síntese química , Microbiologia do Solo , Hypocreales/química , Ressonância Magnética Nuclear Biomolecular , Testes de Sensibilidade Microbiana , Benzaldeídos/química , Benzaldeídos/farmacologia , Antibacterianos/farmacologia , Antibacterianos/química , Antibacterianos/síntese químicaRESUMO
Vanillin is a widely used flavoring compound in the food, pharmaceutical, and cosmetics area. However, the biosynthesis of vanillin from low-cost shikimic acid is significantly hindered by the low activity of the rate-limiting enzyme, caffeate O-methyltransferase (COMT). To screen COMT variants with improved conversion rates, we designed a biosensing system that is adaptable to the COMT-mediated vanillin synthetic pathway. Through the evolution of aldehyde transcriptional factor YqhC, we obtained a dual-responsive variant, MuYqhC, which positively responds to the product and negatively responds to the substrate, with no response to intermediates. Using the MuYqhC-based vanillin biosensor, we successfully identified a COMT variant, Mu176, that displayed a 7-fold increase in the conversion rate compared to the wild-type COMT. This variant produced 2.38 mM vanillin from 3 mM protocatechuic acid, achieving a conversion rate of 79.33%. The enhanced activity of Mu176 was attributed to an enlarged binding pocket and strengthened substrate interaction. Applying Mu176 to Bacillus subtilis increased the level of vanillin production from shikimic acid by 2.39-fold. Further optimization of the production chassis, increasing the S-adenosylmethionine supply and the precursor concentration, elevated the vanillin titer to 1 mM, marking the highest level of vanillin production from shikimic acid in Bacillus. Our work highlights the significance of the MuYqhC-based biosensing system and the Mu176 variant in vanillin production.
Assuntos
Benzaldeídos , Técnicas Biossensoriais , Metiltransferases , Benzaldeídos/metabolismo , Benzaldeídos/química , Técnicas Biossensoriais/métodos , Metiltransferases/metabolismo , Metiltransferases/genética , Ensaios de Triagem em Larga Escala/métodos , Hidroxibenzoatos/metabolismoRESUMO
In this study, we describe a rapid and high-throughput smartphone-based digital colorimetric method for determining urea in milk. A compact and cost-effective 3D-printed image box microplate-based system was designed to measure multiple samples simultaneously, using minimal sample and reagent volumes. The apparatus was applied for the quantification of urea in milk based on its reaction with p-dimethylaminobenzaldehyde (DMAB). The predictive performance of calibration was evaluated using RGB and different colour models (CMYK, HSV, and CIELAB), with the average blue (B) values of the RGB selected as the analytical signal for urea quantification. Under optimized conditions, a urea concentration linear range from 50 to 400 mg L-1 was observed, with a limit of detection (LOD) of 15 mg L-1. The values found with the smartphone-based DIC procedure are in good agreement with spectrophotometric (spectrophotometer and microplate treader) and reference method (mid-infrared spectroscopy) values. This proposed approach offers an accessible and efficient solution for digital image colorimetry, with potential applications for various target analytes in milk and other fields requiring high-throughput colorimetric analysis.
Assuntos
Colorimetria , Leite , Impressão Tridimensional , Smartphone , Ureia , Leite/química , Colorimetria/métodos , Colorimetria/instrumentação , Animais , Ureia/análise , Ureia/química , Limite de Detecção , Benzaldeídos/química , Benzaldeídos/análiseRESUMO
Various crossover phenomena are immanent to supercritical fluids due to multidirectional temperature effects in highly compressible supercritical fluid media. Solubility crossover, i.e. controversial effect of temperature on solubility at different pressures, is probably the most well-known among them. A curious discrepancy in upper crossover pressure values between solubility in supercritical carbon dioxide and retention in supercritical fluid chromatography with pure CO2 as an eluent was unexpectedly observed for several non-polar compounds on different stationary phases. In some cases, retention crossover was found to happen at pressures almost twice as high as pressures for solubility crossover for the same compound. Retention data for three solutes with known solubility crossovers: anthracene, benzoic acid and vanillin, were collected at different pressures and temperatures for several stationary phases. The existence of upper retention crossovers, i.e. such pressure values beyond which temperature increase starts decreasing retention, were registered for all solute-sorbent combinations. Using known thermodynamic models of temperature effect on retention in supercritical fluid chromatography and on solubility in supercritical carbon dioxide, possible reasoning for the observed discrepancies is discussed. Major contribution of the balance between adsorption and partition retention mechanisms in defining retention crossover values is hypothesized.
Assuntos
Dióxido de Carbono , Cromatografia com Fluido Supercrítico , Pressão , Solubilidade , Temperatura , Cromatografia com Fluido Supercrítico/métodos , Dióxido de Carbono/química , Antracenos/química , Ácido Benzoico/química , Termodinâmica , Benzaldeídos/química , AdsorçãoRESUMO
Saliva has emerged as a primary biofluid for non-invasive disease diagnostics. Saliva collection involves using kits where individuals stimulate saliva production via a chewing device like a straw, then deposit the saliva into a designated collection tube. This process may pose discomfort to patients due to the necessity of producing large volumes of saliva and transferring it to the collection vessel. This work has developed a saliva collection and analysis device where the patient operates it like a lollipop, stimulating saliva production. The lollipop-mimic device contains yarn-based microfluidic channels that sample saliva and transfer it to the sensing zone embedded in the stem of the device. We have embedded electrochemical sensors in the lollipop platform to measure vanillin levels in saliva. Vanillin is the most common food flavoring additive and is added to most desserts such as ice cream, cakes, and cookies. Overconsumption of vanillin can cause side effects such as muscle weakness, and damage to the liver, kidneys, stomach, and lungs. We detected vanillin using direct oxidation at a laser-induced graphene (LIG) electrode. We showed a dynamic range of 2.5 µM to 30 µM, covering the physiologically relevant concentration of vanillin in saliva. The lab-on-a-lollipop platform requires only 200 µL of saliva and less than 2 minutes to fill the channels and complete the measurement. This work introduces the first sensor-embedded lollipop-mimic saliva collection and measurement system.
Assuntos
Benzaldeídos , Técnicas Eletroquímicas , Saliva , Saliva/química , Benzaldeídos/química , Benzaldeídos/análise , Humanos , Técnicas Eletroquímicas/instrumentação , Dispositivos Lab-On-A-Chip , Desenho de EquipamentoRESUMO
Different methods of starch modification have been proposed to broaden its application. In this study, the effects of ternary mixtures of natural crosslinking agents: chitosan-betaine-vanillin and gelatin-betaine-vanillin on the properties of pea starch were explored. These combinations of substances were selected because they have complementary crosslinking mechanisms. The effects of the ternary crosslinker mixtures on the gelatinization, mechanical properties, thermal stability, and microstructure of pea starch were compared. Both combinations of crosslinkers enhanced the gelatinization viscosity, viscoelasticity, gel hardness, and thermal stability of the pea starch, by an amount that depended on the ratio of the different components in the ternary mixtures. In all cases, the crystal structure of the starch granules disappeared after gelatinization. The modified starch had a more compact and uniform microstructure than the non-modified version, especially when it was crosslinked by vanillin, gelatin, and betaine. The improvement in the gelation properties of the starch were primarily attributed to hydrogen bonding, electrostatic attraction, and Schiff base crosslinking of the various components present. Gelatin enhanced the gel strength more than chitosan, which was probably because of greater hydrogen bonding. Our findings suggest that the properties of starch can be enhanced by adding ternary mixtures of natural crosslinkers.
Assuntos
Benzaldeídos , Betaína , Quitosana , Reagentes de Ligações Cruzadas , Gelatina , Pisum sativum , Amido , Gelatina/química , Amido/química , Quitosana/química , Betaína/química , Benzaldeídos/química , Pisum sativum/química , Reagentes de Ligações Cruzadas/química , Viscosidade , Géis/químicaRESUMO
We report hydroxyl-functionalized microporous polymers with tunable benzaldehyde groups for gas separation membranes. These polymers were synthesized via acid-catalyzed Friedel-Crafts polycondensation. The tunability in d-spacing and fractional free volume of these polymers depends on the para position substituents (-H, -F, -Cl, and -Br) of the benzaldehyde. Specifically, the size and polarity of the para position substituent influence the polymer chain-packing structure. Consequently, the hydroxyl-functionalized microporous polymer membrane with a larger para position substituent in the benzaldehyde group exhibited improved gas permeability. This improvement is due to enhanced gas diffusivity resulting from the inefficient polymer chain-packing structure. Furthermore, these membranes demonstrated enhanced CO2 plasticization resistance, attributable to the rigid, contorted polymer structure and the hydrogen bonding interactions between hydroxyl groups. This study provides insights into the relationship between the polymer chain-packing structure, tunable para position substituents, and molecular transport.
Assuntos
Benzaldeídos , Polímeros , Benzaldeídos/química , Polímeros/química , Porosidade , Gases/química , Membranas Artificiais , Dióxido de Carbono/química , Ligação de Hidrogênio , PermeabilidadeRESUMO
Vanillin, a key flavor compound found in vanilla beans, is widely used in the food and pharmaceutical industries for its aromatic properties and potential therapeutic benefits. This study presents a comprehensive quantum chemical analysis to elucidate the interaction mechanisms of vanillin with CYP450 enzymes, with a focus on mechanism-based inactivation. Three potential inactivation pathways were evaluated: aldehyde deformylation, methoxy dealkylation, and acetal formation. Aldehyde deformylation was identified as the most energy-efficient, involving the removal of the aldehyde group from vanillin and leading to the formation of benzyne intermediates that could react with the iron porphyrin moiety of CYP450, potentially resulting in enzyme inactivation. Further investigation into the interactions of vanillin with CYP2E1 and CYP1A2 was conducted using molecular docking and molecular dynamics (MD) simulation. The docking analyses supported the findings from DFT studies, wherein vanillin revealed high binding affinities with the studied isozymes. Moreover, vanillin occupied the main binding site in both isozymes, as evidenced by the inclusion of the heme moiety in their binding mechanisms. Employing a 100 ns molecular dynamics simulation, we scrutinized the interaction dynamics between vanillin and the two isozymes of CYP450. The assessment of various MD parameters along with interaction energies revealed that vanillin exhibited stable trajectories and substantial energy stabilization during its interaction with both CYP450 isozymes. These insights can guide future research and ensure the safe application of vanillin, especially in scenarios where it may interact with CYP450 enzymes.
Assuntos
Benzaldeídos , Simulação de Acoplamento Molecular , Simulação de Dinâmica Molecular , Benzaldeídos/metabolismo , Benzaldeídos/química , Inocuidade dos Alimentos , Sistema Enzimático do Citocromo P-450/metabolismo , Sistema Enzimático do Citocromo P-450/química , Humanos , Citocromo P-450 CYP2E1/metabolismo , Citocromo P-450 CYP2E1/química , Citocromo P-450 CYP1A2/metabolismo , Citocromo P-450 CYP1A2/química , Redes e Vias Metabólicas , Teoria da Densidade FuncionalRESUMO
The use of lignocellulosic biomass to create natural flavor has drawn attention from researchers. A key flavoring ingredient that is frequently utilized in the food industry is vanillin. In this present study, Pediococcus acidilactici PA VIT effectively involved in the production of bio-vanillin by using Ferulic acid as an intermediate with a yield of 11.43⯵g/mL. The bio-vanillin produced by Pediococcus acidilactici PA VIT was examined using FTIR, XRD, HPLC, and SEM techniques. These characterizations exhibited a unique fingerprinting signature like that of standard vanillin. Additionally, the one variable at a time method, placket Burmann method, and response surface approach, were employed to optimize bio-vanillin. Based on the central composite rotary design, the most important process factors were determined such as agitation speed, substrate concentration, and inoculum size. After optimization, bio-vanillin was found to have tenfold increase, with a maximum yield of 376.4⯵g/mL obtained using the response surface approach. The kinetic study was performed to analyze rate of reaction and effect of metal ions in the production of bio-vanillin showing Km of 10.25, and Vmax of 1250 were required for the reaction. The metal ions that enhance the yield of bio-vanillin are Ca2+, k+, and Mg2+ and the metal ions that affects the yield of bio-vanillin are Pb+ and Cr+ were identified from the effect of metal ions in the bio-vanillin production.
Assuntos
Benzaldeídos , Ácidos Cumáricos , Pediococcus acidilactici , Ácidos Cumáricos/metabolismo , Ácidos Cumáricos/química , Benzaldeídos/metabolismo , Benzaldeídos/química , Pediococcus acidilactici/metabolismo , Cinética , FermentaçãoRESUMO
Vanillin is a phenolic aldehyde widely used as a flavouring agent in the food industry. Vanillin has many health benefits and has gained attention in pharmacological industries also, due to its antioxidant properties and non-toxic nature. The interaction of vanillin with human hemoglobin (hHb), an abundant tetrameric heme protein, was investigated by several spectroscopic techniques and molecular modeling methods. UV-visible spectra showed that the binding of vanillin to hHb induces structural changes due to alterations in the micro-environment of hHb. Vanillin quenches the intrinsic fluorescence of hHb by the dynamic mechanism, which was confirmed by both temperature dependent and time resolved fluorescence studies. Vanillin binds spontaneously to hHb at a single site and the binding is stabilized by hydrogen bonds and hydrophobic interactions. The circular dichroism spectra showed that the binding of vanillin altered the secondary structure of hHb due to change in its alpha-helical content. Molecular docking identified the amino acids of hHb involved in binding to vanillin and also that the free energy change of the binding reaction is -5.5 kcal/mol. Thus, our results indicate that vanillin binds spontaneously to hHb at a single site and alters its secondary structure. This will help in understanding the potential use of vanillin and related antioxidants as therapeutic agents in various hematological disorders.
Assuntos
Benzaldeídos , Dicroísmo Circular , Hemoglobinas , Simulação de Acoplamento Molecular , Espectrometria de Fluorescência , Benzaldeídos/química , Benzaldeídos/metabolismo , Humanos , Hemoglobinas/química , Hemoglobinas/metabolismo , Espectrofotometria Ultravioleta , Ligação Proteica , Termodinâmica , Plantas/química , Plantas/metabolismoRESUMO
An investigation of reversible protein conjugation and deconjugation is presented. Despite numerous available protein conjugation methods, there has been limited documentation of achieving protein conjugation in a controlled and reversible manner. This report introduces a protocol that enables protein modification in a multicomponent fashion under aqueous buffer and mild conditions. A readily available mercaptobenzaldehyde derivative can modify the primary amine of peptides and proteins with a distinctive [3.3.1] scaffold. This modification can be reversed under mild conditions in a controlled fashion, restoring the original protein motif. The effectiveness of this approach has been demonstrated in the modification and quantifiable regeneration of insulin protein.
Assuntos
Peptídeos , Proteínas , Peptídeos/química , Proteínas/química , Estrutura Molecular , Benzaldeídos/química , Insulina/químicaRESUMO
DNA and RNA nucleobase modifications are biologically relevant and valuable in fundamental biochemical and biophysical investigations of nucleic acids. However, directly introducing site-specific nucleobase modifications into long unprotected oligonucleotides is a substantial challenge. In this study, we used in vitro selection to identify DNAzymes that site-specifically N-alkylate the exocyclic nucleobase amines of particular cytidine, guanosine, and adenosine (C, G and A) nucleotides in DNA substrates, by reductive amination using a 5'-benzaldehyde oligonucleotide as the reaction partner. The new DNAzymes each require one or more of Mg2+, Mn2+, and Zn2+ as metal ion cofactors and have kobs from 0.04 to 0.3 h-1, with rate enhancement as high as â¼104 above the splinted background reaction. Several of the new DNAzymes are catalytically active when an RNA substrate is provided in place of DNA. Similarly, several new DNAzymes function when a small-molecule benzaldehyde compound replaces the 5'-benzaldehyde oligonucleotide. These findings expand the scope of DNAzyme catalysis to include nucleobase N-alkylation by reductive amination. Further development of this new class of DNAzymes is anticipated to facilitate practical covalent modification and labeling of DNA and RNA substrates.